Dismal Results On Bolt Thrust Experiment #2

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Dismal Results On Bolt Thrust Experiment #2

Post by Sixgun »

Today I made a cool video using a first year production 1894 Marlin short rifle in 44-40. I took out the locking bolt and the lever, leaving a free sliding bolt. I had to use duct tape to hold the bolt closed because of the ejector. ...........I first tried a primed case and zilch.....would not fire.......Then I inserted the lever and tried it again.....zilch.......then I put the locking bolt in without the lever......zilch

I guess the designer had good thought because of idiots like me and retart-proofed it. Then the light bulb came on and I forgot about the two piece firing pin which requires all of the parts to be in, in order for it to work.

It's now Sat. afternoon and I need to play so I'm not Obama-rigging it to work. (Hey! That's an idea, maybe if I paint the gun white, it will work! And I not pulling apart a 92 as it's more work intensive.

On to the York, Pa. gunshow tomorrow.------6

Howdy guys,
I made this 10 cent video today and its all about my previous post on "bolt thrust". The gun used was one of my earliest Colt Lightning rifles, serial # 58. These early Colts did not have an action locking device except for a little lever that kept the action closed while walking around.

Caliber is 44-40 and load is 6 gr. of Bullseye with a 200 gr. Hensley & Gibbs cast bullet. Velocity is almost 1100 fps.

Keep in mind that supposedly only low pressure rounds do not have bolt thrust according to John Barsness of Handloader magazine.

I'm no engineer or ballistician, or for that matter, not even college educated. I'm just a regular guy who shoots a lot and would really like to know the truth on bolt thrust.

I mentioned in the video that I was using a 170 gr. Lyman bullet, but its the 200 gr.-----------Sixgun

http://www.youtube.com/watch?v=k1uPV84Z ... e=youtu.be
Last edited by Sixgun on Sat Oct 26, 2013 12:31 pm, edited 1 time in total.
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Re: Video Of Bolt Thrust

Post by KWK »

I'd say that's worth much more than 10 cents.

What to make of it, I don't know. Lyman's data suggests that's running 8 to 9 thousand psi. I'm amazed Colt designed a gun with no breech locking at all; I was not aware of that. If I understand what you're saying, there's only the friction of the slide mechanism plus the hammer to retard the bolt -- wow! That it works is also impressive. I'd like to see a scale drawing of the mechanism, but I know I have none in any book I own. I'll have to search the web.

Did Colt proudly put a patent number on the gun? There might be more information in such a patent.

Thanks for posting. Nice gun, by the way.
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Re: Video Of Bolt Thrust

Post by Sixgun »

KWK wrote:I'd say that's worth much more than 10 cents.

What to make of it, I don't know. I'm amazed Colt designed a gun with no breech locking at all. If I understand what you're saying, there's only the friction of the slide mechanism to retard the bolt -- wow. That it works is also impressive. I'd like to see a scale drawing of the mechanism, but I know I have none in any book I own. I'll have to search the web.

Thanks for posting.
KWK,
I can only report the facts as I see them. I have other Lightnings that are later models and they not have that little lever and the action stays locked once the hammer is on the safety notch. As I am in the crowd of guys who also play with the old guns, an associate of mine told me he has an early large frame Lightning in 45-85 and it works the same way as my early Colt, so I am quite sure these guns were manufactured this way. My acquaintance was telling me he thought his gun was broke, but as he is a little nuts like me, he went ahead and shot it. When he saw everything was OK, he has been shooting it a lot over the years.-----------6
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Re: Video Of Bolt Thrust

Post by Tycer »

That's great!
Kind regards,
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Re: Video Of Bolt Thrust

Post by KWK »

Well, I found a picture of the patent dates on a medium frame frame, but google didn't locate the patent numbers. I'll have to do it the hard way.

A drawing I found of the internals of the medium frame shows a locking brace attached to the bolt inside. Did the early models lack these?
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Re: Video Of Bolt Thrust

Post by Sixgun »

KWK,
I don't know if there is a locking brace in the early variation. I have to be up in about 6 hours so I'm going to get some shut eye and when I get home tomorrow, I'm going to take two of the Lightnings apart and do a look-see.-----6
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Re: Video Of Bolt Thrust

Post by Griff »

I still ain't convinced. It seems counter-intuitive to believe that a low pressure round has no bolt thrust. If I were to theorize, I'd say that a low pressure round that doesn't quite seal the chamber with the case, causing blow-by into the action would have MORE bolt thrust than a higher powered load that does expand the case enough to seal the chamber.

Am I wrong? Missing the point of the discussion? Or just being obtuse?

Conversely, even a higher pressure rounds must exert some bolt thrust in that period between bullet release and case expansion to fill the chamber.

Am I still wrong? Missing the point, or being obtuse? Like Sixgun, I aint' an engineer, flunked out of college math... squeeked by with the VERY minimum requirements...
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Re: Video Of Bolt Thrust

Post by earlmck »

OK, if there is no locking brace, lug, whatever and that baby stays closed, there must be awful close to zero bolt thrust with that load. Quickload estimates about 13K psi for that 6gr. Bullseye/200 Lyman if your load length is standard...

A fine 10 cent video, Sixgun.
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Re: Video Of Bolt Thrust

Post by Nate Kiowa Jones »

Six, I don't know man, Ive worked several original early to late and the repros, too. and everyone had the locking brace. Now if you are talking action slide stop, for the later version it hold the slide forward until the trigger drops. The earlier versions were different. i just don't remember just how.

The locking brace is part 170. It's pinned and hinges down off the bottom of the bolt to brace against the trigger plate #26 when the action slide is fully forward. it acts somewhat like a chair shoved under a door knob.
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Re: Video Of Bolt Thrust

Post by Sixgun »

Well, boys, looks like we have a challenge on our hands. This sure beats "does a cast bullet lead the barrel?" Just rolled outta bed and I have to go put my 8 hours in. Will play later.---6
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Re: Video Of Bolt Thrust

Post by kevind6 »

Looking at the shape of the hammer in the schematic the hammer itself acts as a locking lug......similar to the Remington rolling block action. The hammer in the forward position, such as it is when being fired, blocks the bolt from coming back. The key is can you cycle the action with the hammer forward?? I'm not familiar with the gun, but I'm guessing no.
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Re: Video Of Bolt Thrust

Post by J Miller »

Sixgun,

Interesting video. I'd love to have one of those to play with.

Now my curiosity is this; how would that rifle act with a period correct black powder load? I know Bullseye is a fast burning powder that builds pressure very quickly, but it's not what existed when that rifle was designed. Just curious about that.

Oh, and the rifle report sounded like someone off to the right slapped two boards together when you fired it.

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Re: Video Of Bolt Thrust

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kevind6 wrote:Looking at the shape of the hammer in the schematic the hammer itself acts as a locking lug......similar to the Remington rolling block action. The hammer in the forward position, such as it is when being fired, blocks the bolt from coming back. The key is can you cycle the action with the hammer forward?? I'm not familiar with the gun, but I'm guessing no.

Dang! You might have something there! Lets wait a little 'till the smart guys hear this.

Joe, The sound of the cartridge is very muffled as I was near shooting point blank into a bullet stop.----6

Aint this somethin'? The bosses must have turned off the "Websense".
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Re: Video Of Bolt Thrust

Post by AJMD429 »

Sixgun wrote:Well, boys, looks like we have a challenge on our hands. This sure beats "does a cast bullet lead the barrel?"
Yep. Amazing that there is still some very basic stuff that we don't know, and that stuff that was probably 'common knowledge' a century ago, like how and why these designs worked, is having to be 'rediscovered' now.

Cool stuff...!

BTW - the 444 Marlin is better than the 45-70, but 45 Colt beats 44 Mag, and no way is a 30-06 half as good as a 308... :lol:
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Re: Video Of Bolt Thrust

Post by w30wcf »

Sixgun,
Great video! You da man! It will be interesting to know if something other than the hammer is holding the action closed.

I think I'm going to take a .44-40 case and increase the headspace .015" by removing that portion of the rim on the case body side. Then I will place a small amount of clay around the case head away from the primer. After being fired in my '73, if the clay is the same thickness as the primer protrusion that would indicate that the case head never made contact with the bolt.

It will be a week or 2 before I have the chance to try this. I will report back then....

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Re: Video Of Bolt Thrust

Post by JRD »

Sixgun,
I've only disassembled one medium frame Lightning- a 44 baby carbine. It was 1886 vintage as I recall. It most definitely has a locking mechanism. Don't confuse the slide handle not being locked forward with the bolt not being locked. Part 170 in the exploded view definitely does lock the bolt and is automatically engaged and disengaged as you finish closing or start opening the pump for end.

Try this: Close the action fully. Then slide a cleaning rod down the barrel and push on the breech face. If the slide is fully closed, the bolt won't open no matter how hard you push because locking mechanism (170) is engaged. Now retract the slide handle a fraction of an inch and push on the breech face again. The bolt should get pushed open because the locking mechanism was disengaged by moving the pump handle backward.

The Lightning is somewhat unconventional compared to the pumps we have come to know and love like Winchesters and Remington's that lock the slide forward until you fire the mechanism.

I assure you that without part 170 the Lightning would come flying open if you fired it.

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Re: Video Of Bolt Thrust

Post by 3leggedturtle »

Six, pretty neat rifle, the report sounds like a big 22 with the supersonic crack. I was thinking to, there has to be something with the hammer that locks the bolt when it is fired. You don't talk and sound near as gruff as you type. Have you chronoe'd yer loads? Sound llike they should be doing 1160fps or so.
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Re: Video Of Bolt Thrust

Post by Chuck 100 yd »

I am in Griff`s camp on low pressure cartridges and bolt thrust.
If the case does not expand due to chamber pressure the case would not grip the chamber wall and the thrust would be greater than if it had expanded to grip it.
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Re: Video Of Bolt Thrust

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Well, JRD has turned out to be a party pooper........and a smart one at that. I took his suggestion and ran a heavy diameter brass rod down the bore and tapped on the bolt face while the pump handle was up and the action closed........the action stayed still, very solid. Then I just pushed on the handle a tad and ran the rod down again but this time the action opened up.....mystery solved....at least as far as the Colt Lightning is concerned. Thanks Jason !

There were some smart people back in the day, ingenious lock up.

This makes me wonder....why would a well known respected gun writer like John Barsness make a statement like that in a magazine without knowing the absolute truth?

When I get some time this coming weekend, I'm gonna take out the locking bolts on an 1892 Winchester and do some more shooting, starting with extremely light loads.-------6
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Re: Video Of Bolt Thrust

Post by KWK »

Sixgun wrote:... ingenious lock up.
One mystery solved. I do hope the hammer is blocked by the time the breech is unlocked!
I'm gonna take out the locking bolts on an 1892 Winchester and do some more shooting, starting with extremely light loads.
Oooo, I wouldn't do that, at least not with a '92 of any value -- and a very long string.
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Re: Video Of Bolt Thrust

Post by Ysabel Kid »

Serial number 58!?! How do you find these treasures?!? :mrgreen:
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Re: Video Of Bolt Thrust

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Ysabel Kid wrote:Serial number 58!?! How do you find these treasures?!? :mrgreen:
Kid, I don't find them, they find me....-6
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Re: Video Of Bolt Thrust

Post by Griff »

Sixgun wrote:This makes me wonder....why would a well known respected gun writer like John Barsness make a statement like that in a magazine without knowing the absolute truth?
Because he got paid to write an article... either on his boss' theory or Barness' theory.

Take a theory, any theory, and then write a bunch of words around it... make it sound scientific, and of no one can disprove it, you're golden! And since he doesn't define what he's calling "low pressure", it pretty hard to disprove. While a 45 Colt is a lower pressure round than the .30-30, and it in turn, is lower than the .45 Magnum... it becomes a game of chasin' your tail. However, I'll bet that an 8,000psi 45 Colt round has MORE bolt thrust than a 12,000psi 45 Colt round. If, and it's a big IF, that 8,000psi load doesn't expand enough to allow the case to grip the chamber walls. And, even if it does, is there a moment in the span of ignition where maybe the higher pressure round does put more bolt thrust on the bolt? A true life conundrum.
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Re: Video Of Bolt Thrust

Post by Old Savage »

Six, sometimes the boys just don't know when you are funnin' 'em. :D No locking mechanism - that sure it a good one. :D

Griff - question - will a loose case move backward faster than the brass expands? Could get complicated.
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Re: Video Of Bolt Thrust

Post by Nate Kiowa Jones »

Sixgun wrote:Well, JRD has turned out to be a party pooper........and a smart one at that. I took his suggestion and ran a heavy diameter brass rod down the bore and tapped on the bolt face while the pump handle was up and the action closed........the action stayed still, very solid. Then I just pushed on the handle a tad and ran the rod down again but this time the action opened up.....mystery solved....at least as far as the Colt Lightning is concerned. Thanks Jason !

There were some smart people back in the day, ingenious lock up.

This makes me wonder....why would a well known respected gun writer like John Barsness make a statement like that in a magazine without knowing the absolute truth?

When I get some time this coming weekend, I'm gonna take out the locking bolts on an 1892 Winchester and do some more shooting, starting with extremely light loads.-------6
Best not try that with a 92. You can get by doing that to a Win 94 or a 1894 marlin. They both have lever hinge points at the breech bolt and on the link or trigger plate. This is what Ackley did. In essence he was using the lever like the chair under the door knob.
But, the 92 doesn't work like that. It hinges off the pin through the breech bolt and the pin through the the locking bolts.
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Re: Video Of Bolt Thrust

Post by KWK »

Nate Kiowa Jones wrote:This is what Ackley did.
Doh! Why didn't I see that? Thanks for pointing it out.
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Re: Video Of Bolt Thrust

Post by Sixgun »

OS,
I ain't funnin no one. I want to know for sure even though common sense tells me the bolt will come flying back.

I'll try a new game, I'll even disconnect the lever and see how far I can make the bolt fly. This is gonna be good!---6
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Re: Video Of Bolt Thrust

Post by Borregos »

Sixgun wrote:OS,
I ain't funnin no one. I want to know for sure even though common sense tells me the bolt will come flying back.

I'll try a new game, I'll even disconnect the lever and see how far I can make the bolt fly. This is gonna be good!---6
We will need a video of that for sure :D :D
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Re: Video Of Bolt Thrust

Post by BenT »

Educational and entertaining ! You can't just get that anywhere. :D
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Re: Video Of Bolt Thrust

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Griff wrote:. . . I'll bet that an 8,000psi 45 Colt round has MORE bolt thrust than a 12,000psi 45 Colt round. If, and it's a big IF, that 8,000psi load doesn't expand enough to allow the case to grip the chamber walls. And, even if it does, is there a moment in the span of ignition where maybe the higher pressure round does put more bolt thrust on the bolt? A true life conundrum.
True - think of a hammer tapping a nail lightly - there is an instantaneous force that is fairly high, but so quick that if you tapped that lightly into the palm of your other hand, the hand would barely move.

There is quite a bit of 'friction' and 'timing' and 'areas under the curve' and 'momentum' and all sorts of stuff going on here - way different than the physics of a muzzleloader, where you essentially have a cylinder sealed on one end, with a lead piston and an expanding combustion mixture. The only fuzzy part there is the 'leak' of the passage covered in the percussion ones by a primer-cup held down momentarily by a hammer-spring. With modern cartridge guns, you not only may have a 'bottle neck' situation where the chamber diameter is far bigger than the bore diameter (and that very shape contributes variously to rearward movement of the cartridge), but the rear of it is essentially completely 'open', having some bolt or falling block just roughly contain a chunk of movable brass 'gasket'. Add to that the variety of pressures from 22 Short or 25 ACP all the way up to 454 Casull, 7mm Remington UltraMag or 50 BMG, and case shapes of all sorts, and it gets complex, to say the least...!
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Re: Video Of Bolt Thrust

Post by rbertalotto »

And let's add cartridge head diameter. The larger the head, the greater the pressure. Andrade have been written about this for the TC Contender. Same cartridge pressure but the action could handle 223 head thrust, but not 308 or even 300 Savage.
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Re: Video Of Bolt Thrust

Post by Old Savage »

ID of the cartridge at the base.

Should be interesting test Six.

My apologies Six - I went back and re read or actually read the premise of your OP on the original bolt thrust thread. Had not recalled what a central point to the thread the supposed lack of locking mechanism in the Lightning was.
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Re: Video Of Bolt Thrust

Post by Sixgun »

OS,
Right! (you da man!) Really, I have always somewhat believed what a professional in any distinct field said was true...you know, they know what they are talking about. Or why else would we go to the doctors? :D

Nothing in my 40+ years of playing with guns have I ever been so dumbfounded by common sense vs. educated physics.

I'm gonna do that, with the bolt thing. I'll stack up a few bales of hay and let that bolt fly!

Of course a video will be included. How else am I going to get my 15 minutes of fame? :D ----6
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Re: Video Of Bolt Thrust

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Sixgun wrote:Of course a video will be included. How else am I going to get my 15 minutes of fame? :D ----6
Famous last words from a 'redneck'....

"Hey y'all, watch THIS. . . :D ". . . :o :shock: :| :(
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Re: Video Of Bolt Thrust

Post by Sixgun »

AJMD429 wrote:
Sixgun wrote:Of course a video will be included. How else am I going to get my 15 minutes of fame? :D ----6
Famous last words from a 'redneck'....

"Hey y'all, watch THIS. . . :D ". . . :o :shock: :| :(
Yea! Thats me! Someday I'll tell you about the snowmobile and the ramp I made.---6
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Re: Video Of Bolt Thrust

Post by Nate Kiowa Jones »

Sixgun wrote:
AJMD429 wrote:
Sixgun wrote:Of course a video will be included. How else am I going to get my 15 minutes of fame? :D ----6
Famous last words from a 'redneck'....

"Hey y'all, watch THIS. . . :D ". . . :o :shock: :| :(
Yea! Thats me! Someday I'll tell you about the snowmobile and the ramp I made.---6

OK, I'll hold your beer. :lol:
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Re: Video Of Bolt Thrust

Post by Sixgun »

Nate Kiowa Jones wrote: OK, I'll hold your beer. :lol:
Steve,
The above is one of the reasons I quit drinking when I was 40. I got more scars and have had more broken bones than you can shake a stick at.

Someday I'll tell you guys about the brand new Trans Am with an HO 400 that had 4000 miles on it when me and this great big Beech tree had an argument on who was tougher.

I'm excited now. I'm headed downstairs and am going to take your advice and pull apart an old 94 Marlin. Watch this guys , Can someone hold my beer? :D ----6
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Nath
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Re: Video Of Bolt Thrust

Post by Nath »

Nice vid six.

Time.....time is the key (IMVHO). The actual time period of high pressure is very short.
In my humble opinion the thrust is conducted to the chamber wall before it bears completely on the bolt, the chamber part of the barrel conveying the recoil force.
There is some co-relation with the bolt and pressure....observed easily when a bolt handle is fouled on a stock etc inducing a zero shift or group size change...time....its short. A small consideration not to be missed!
I also believe our old gun designers knew this and hence their often light locking systems.
Modern lock ups seem stronger made but I think liability law suits are behind it more than a bolt thrust issue.

Anyway....good topic.

N.
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Re: Video Of Bolt Thrust

Post by BigSky56 »

Jack heres a report of some testing by a guy that was posted on another forum, I had read and finally remembered where. danny

This is not my test but a post on the Beartooth forum from 2003

Just my two cents worth on BACKTHRUST......

Let me start by saying that I have been a Riflesmith for over 20 years. I have chambered literally thousands of barrels, designed and developed muzzle brakes for myself, customers and military and law enforcement. I have built hundreds of complete custom rifles for people all over the world, includind law enforcement and military. I have made my own barrels and have designed and developed 62 cartridges to date! My latest being on the 45/70 case, necked down to 6mm and up to .358 caliber. When I'm not working, I'm tinkering and when I'm not doing that, I'm loading and when I'm not doing that, I'm trying to develope a diffrent wildcat cartridge, and on and on and on...............

The Test: Since I do alot of rechamberings on the T/C Contenders, this is what involved the main area of testing. I took several barrels that I had, to the range where a friend and I had built a "stand" to hold a special vice and fixture that we had made specifically for the testing of these Contender barrels. The barrels were locked into this fixture WITHOUT the use of a frame. A "firing device" that was attached to each barrel, via the rear mounting holes in place of a scope base.

The first test involved firing the 30-30 Ackley Improved. With no case head support what so ever, a round was fired and it was found that there was "0" rearward movement of the case! All loads tested were full power hunting and target loads, with the chamber wiped out with alcohol and dried, before the next round was fired. Everything had to be exact, round after round. The test was repeated five times for each cartridge listed. All 5 30-30 Improved cartridges showed "0" backwards movement....

The next test involved the 250 Savage Ackley Improved. Again, all 5 cartridges showed "0" rearward movement when the were fired and two of the cases were actually .002 "deeper" in the chamber after they were fired than before. Reason being, the strike of the firing mechanism had sufficient enough force to drive them further into the chamber....

Next in line was the 7mm T/CU. Same thing as the rest. NO REARWARD MOVEMENT - meaning, absolute ZERO BACKTHRUST!!!

Next came the 35 Remington. well, this was a horse of a diffrent color. This case shot out of the chamber end so fast, that it removed my "firing machanism" with it! I went back and made another one, with slight modifications. I fired off the other four rounds and they all "shot" out the chamber end as well. I set up a piece of pine 2X12 three feet behind the chamber when I went to fire off the last round and that case blew right through it!!!

The next round to be fired was the good ole 30-30 Winchester. It did exactly the same as the 35 Remington! I decided to set my chronograph up behind the chamber to see if I could get a reading on these "projectiles" coming out of the chamber end. I did, it did and I clocked that sucker moving out at 1900 fps!!!

Next was the standard 250 Savage. This was the only one I tried factory ammo in. All of the others were handloads that were developed for those barrels and all of them had the bullets out to touch the rifling. I did shoot two handloads in the 250 Savage as well but all tests were the same. All of the 250 Savage loads exited the "chamber end" at well in excess of 2,000 fps....

I have found that it all boils down to this: if you have a clean and dry chamber and an "Improved" case, meaning "minimum body taper", that when the round is fired, you transmit next to zero or zero backthrust against the frame or bolt! Cases that have a "taper", will always transmit a heavy backthrust against the frame or bolt! How much backthrust it transmits will depend on the taper of the case. Naturally, the greater the taper, the greater the pounding....

Like I said, this is just my two cents worth. I learn something new everyday and learned alot in performing these tests. It has helped me alot in the design and development of my own wildcat cartridges....

Everyone take care and GOD BLESS.

DAVID
Last edited by BigSky56 on Fri Oct 25, 2013 6:21 pm, edited 1 time in total.
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Re: Video Of Bolt Thrust

Post by Borregos »

Very interesting Danny, glad you found it :D
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Re: Video Of Bolt Thrust

Post by 3leggedturtle »

Nice post Big Sky. What pressure were you loading the 250AI to in the Contender? What would be a safe operating pressure for it. I find it interesting MGM would chamber Contender in 250Savag, but not 250AI. Todd/3leg

Would the JDJ line of cartridges show no rearward thrust on your barrel too if you were so inclined to chamber one? Specifically the 257JDJ. thanks
30/30 Winchester: Not accurate enough fer varmints, barely adequate for small deer; BUT In a 10" to 14" barrelled pistol; is good for moose/elk to 200 yards; ground squirrels to 300 metres

I dont call it a long Colt for the same reason I dont call it a short Auto!
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Re: Video Of Bolt Thrust

Post by Sixgun »

Danny,
That was super! Thanks for taking the time to post that. I'm sure a lot of guys here will be commenting all weekend on that one.

John Barsness did say "low pressure" rounds and I'm really not sure if the 30-30 or 35 are low pressure, bordering on 40K. I consider low pressure to be like the stuff I shoot, 12-28K. I mentioned earlier in my post that I once had a S&W Model 53 in 22 Jet and I got rid of it for the same reason others got rid of theirs 45-50 years ago.....it locked up even with mild loads.......not all the time but enough to aggravate the s*3t out of me. I was always sure to have the chambers and ammo free of any lubricant. I used to dunk the cylinder in carb cleaner before going to the gunclub.

You might have saved me the time to dismantle one of my leverguns here and do some testing with an unlocked bolt. Naaaaaa I need a little excitement this weekend! :D Thanks bud!-----------------------6
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Re: Video Of Bolt Thrust

Post by BigSky56 »

Jack besides AI'ing a cartridge and Iam just wondering out loud now what if a person would burnish a chamber such as your jet or another that has a tough time of staying put just something else to chew on I guess. Have a safe weekend Iam heading out for elk & moose in the morning.
3LT it wasnt my test I just copied it from another forum it was posted in 2003 on Beartooth forum and I was remiss in posting that. danny
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Re: Video Of Bolt Thrust

Post by AJMD429 »

If he hadn't tested a variety of cartridges we could make some dangerous assumptions...!

Who'd a thunk a 35 Remington would blow the case through a 2" thick board, yet a 250 Savage would not even move. . . but only if is has been 'Ackleyized'. . . ?
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Re: Video Of Bolt Thrust

Post by Sixgun »

Good luck Danny! :D Give 'em a 200 grainier from a 348!

Doc, (And others)
Do you get the feeling that the more we get into this subject, the more confused we are getting? At least I am. Some stuff has been confirmed but more questions keep coming up.

I just got to play tomorrow and send a bolt skyward. :D -----6
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Re: Video Of Bolt Thrust

Post by KWK »

BigSky56 wrote:Just my two cents worth on BACKTHRUST... DAVID
I really wish the fellow had a 10 cent video to go with that! Frankly, I do have trouble seeing how this could possibly be. Brass just isn't all that strong, and the case isn't very thick.

The original forum thread is at Beartooth. Later in the thread, he says he did the work circa 1990.

He also says the primers didn't back out much unless a case had been loaded hot many times.
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Re: Video Of Bolt Thrust

Post by ollogger »

Sixgun wrote:Good luck Danny! :D Give 'em a 200 grainier from a 348!

Doc, (And others)
Do you get the feeling that the more we get into this subject, the more confused we are getting? At least I am. Some stuff has been confirmed but more questions keep coming up.

I just got to play tomorrow and send a bolt skyward. :D -----6

Yes Danny hope ya see just what your looking for
Six careful out there!!!!!!!!!!

After Danny's post is any body un confused as to why Uberti is putting a 357 in a 73?

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Re: Video Of Bolt Thrust

Post by Sixgun »

Ollogger,

Ha! If you only knew the experiments I put that 25-35 through!


Na, you know better. Say "hi" to Boots. She is not posting enough!-----6
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Re: Video Of Bolt Thrust

Post by Grizzly Adams »

KWK wrote:
Sixgun wrote:... ingenious lock up.
One mystery solved. I do hope the hammer is blocked by the time the breech is unlocked!
I'm gonna take out the locking bolts on an 1892 Winchester and do some more shooting, starting with extremely light loads.
Oooo, I wouldn't do that, at least not with a '92 of any value -- and a very long string.
As I recall, PO Ackley did just that very thing with an W1894. He removed the breach bolt lock and fired the rifle (30-30) without any ill effects, or without the action coming open, thus demonstrating the lack of bolt thrust.

......Ackley used a string....I think! :D

I know that tapered cases generate more bolt thrust than straight walled cases. The 348 WCF will generate considerable bolt thrust with an oiled chamber while a 45-70 will not. I always make sure the chamber in my 71 is clean and dry.
Last edited by Grizzly Adams on Fri Oct 25, 2013 8:23 pm, edited 1 time in total.
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Re: Video Of Bolt Thrust

Post by Ben_Rumson »

Hey Six ... A suggestion... At some point try your test with some freshly annealed cases... Cases that are resized before annealing... & if you wanted to measure the case length of the annealed case be fore firing we might see something there too... Best of luck!
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