what's the average bore diameter of Pre Remington

[S.B.]

Marlin .45/70 rifles?
Steve

[Old Savage]

I believe when I slugged mine the groves were .457" and the bore was .450".

[S.B.]

I believe when I slugged mine the groves were .457" and the bore was .450".

Not to be noisy or rude but, just how much experience do you have with a micrometer? Ever measure microns with a micrometer?
Steve

[pwl44m]

OK U have one , now U need several more to get an Average. But I fear others will be reluctant to say.
Perry

[Old Savage]

Well S.B. - not enough to know what you are getting at.

BUT, I do know that the gal on my right/your left is taller than the one on my left/your right regardless of how the camera makes it look.

[pwl44m]

And They r both taller than U OS, by about a mm.
Perry

[6pt-sika]

I never slugged any of the Marlin 45-70's I had .

I can however tell you I origianlly used home cast wheelweight alloy bullets that were sized at .459" and they shot very well .

Later I bought a .461" sizing die from Buffalo Arms and tried the same bullets sized 2 thousandths more and they shot BETTER !

[Nicknack]

Slugged my Marlin Cowboy Groove Diameter =.457

[yooper2]

Mine is about 15 years old and also runs .457" in the grooves, .450" in the bore. I've found the rifle to be incredibly forgiving regarding bullet diameter.

Eric

[S.B.]

Old Savage, no digs meant at all. I've used them enough to know some use them as "C" clamps instead of precision measuring devices. It never hurts to have another opinion. I think mine measures right at .459?
Very nice looking girls there. Merry Christmas to all and have a happy and prosperous new year.
Steve

[bgmkithaca]

I have slugged three CB barrells , came out at .457 and .450 plus or minus about 2 ten thousndths. All of them had tight spots at the dovetails to some degree.

[junkbug]

You did not bother to ask whether anyone was measuring a micro-groove, or ballard groove barrel.

[Old Savage]

Gotcha S.B., I take a light touch approach to things. And - if you are going to compare the gals - they have be both be on the same side, in this case the right/your left - - with a light touch of course



BTW - I used a caliper.

[Pitchy]

BTW - I used a caliper.

Myself i use a ruler to measure mine.

[3leggedturtle]

I went Harbor Tool n Freight and got a pair of their "precision" plastic calipers.

[Old Savage]

Pitch - that's how to do it. Could you do us a pictorial or video so we can get that right on

[Pitchy]

Pitch - that's how to do it. Could you do us a pictorial or video so we can get that right on

Naw i don`t like to brag, just entertain.
Merry Christmas OS and family

[Old Savage]

And to you to Pitchy. But, the video would help me see EXACTLY what you are getting at

[Pitchy]

No show and tell here

[Catshooter]

You don't say why you'd like to know an average bore size. But I can tell you that if you're trying establish what you should size your cast bullets to the best route to sucess with cast isn't by using someones else's 'average'.

Bores vary. Sometimes alot. Nominal for a .357 is supposed to be just that. I've measured them from .355 to .3598. Forty fives can be worse and often are.

I've a 45-70 that is almost .460, my brothers of the same brand is just barely .456.


Cat

[Charles]

I have one of the Marlin 45-70s with the Ballard rifling. It measures .458 with a fine, properly adjusted and properly used (50 years experience) Starrett micrometer.

Marlins require larger cast bullets not because the land groove diamter is larger than normal, but the throat is larger than normal. I had a sizing die honed out to .460 and get excellent accuracy with the RCBS 405 FN. This bullets casts at .4595 and the .460 die just lubes and seats the gas checks.

[S.B.]

catshooter, you sound a little rude and presumptous, I see you don't have many posts here. New? I've sized mine but, thought maybe I'd errored in my measurement? Thought maybe Marlin would hold tighter tolerances.
Steve

[Old Savage]

What size do you get on your measurements?

[S.B.]

.4595
Steve

[Catshooter]

SB,


When I read your post it made me wonder as it's often difficult for me to communicate clearly with the written word. So I went back and re-read my post.

Maybe I'm wrong, (been there before) but it doesn't seem like I screwed up. I'm pointing out facts that I'm hoping can maybe help you. Since you ask a very simple question with no other data or back story it's a little tough to provide a specific, technical answer.

My post shows my join date. Kinda presumptius of you to not even bother to look and see what it was.


Cat

[1894c]

i have a list by Beartooth Bullets that give the basic diameters of all Marlin Groove Bullet Diameter. (pre-REM)--see attached graphic ... :)

[rhead]

Mine measures .458 and .450. My chamber throat is .463 and it shoots best with a 405 grain bullet sized to .462.

It has been my experience that if the throat area is oversize which is common in today's market sizing to fit the throat is worth trying.

[S.B.]

Thanx 30wcf, just what I was looking for.
Steve

[Old Savage]

30wcf - would you happen to have avg bore and groove diameters for the Ballard rifling and recommended bullet sizes?