OT- Revolver Accuracy

[336A]

I have a couple of questions that I hope the experienced members here can help me with. I was out shooting my S&W M10 the other day at 10yd trying to keep all the shots inside the 2 inch bulls eye. However I seem to have a meesed up cylinder which throws a round away from the rest of the group by about 1 inch. So what is the cause of this and how do i go about fixing it. Also is this common in revolvers? I was under the impression that the S&W M10 was more accurate than this and should have no problem punching out the center of the target at this distance.

[J Miller]

I have a couple of questions that I hope the experienced members here can help me with. I was out shooting my S&W M10 the other day at 10yd trying to keep all the shots inside the 2 inch bulls eye. However I seem to have a meesed up cylinder which throws a round away from the rest of the group by about 1 inch. So what is the cause of this and how do i go about fixing it. Also is this common in revolvers? I was under the impression that the S&W M10 was more accurate than this and should have no problem punching out the center of the target at this distance.

336A,

Most revolvers are far more accurate than we humans can shoot them. However once in a while you'll come up with one with with a bad chamber.
The best way to check it is to shoot groups from the bench and mark the chamber that throws the flier. See if it's the same each time. If it is then a chamber cast or slugging the throats is in order.

I've had several S&W 38s and all of them were excellent shooters.
If it turns out the cylinder is faulty a call to S&W's service dept is in order.

Joe

[Griff]

To determine a revolver's accuracy, 1st you have to remove the human element from the long list of variables. If you don't own a Ransom Rest, you can still go a long way to keeping the human from swaying the results.

Your distance is good as you want to be able to see the rear and front sights and the target. However, I like a bit further, where I can't see the individual holes appear... believe it not, I think that tends to make one "chase" the group, rather than focusing on the bull and concentrating on the sights.

I like a good sized block of wood, 6"x6" or even 8"x8" with a sand bag on top. A good, two-handed grip is essential, with the front web of the trigger guard or frame with the barrel resting directly on the sandbag or even two. I still use my old canvas shot bags filled with sand and sewed shut as range bags. Leave the good leather one for your rifle. You'll tear up a sandbag if you have any lead cutting on the breech of the barrel, but... this provides a very steady rest from which to do your testing.

Next is the ammo... you want the best you can provide. If you don't handload, pretty much any of the .38 Special wadcutters will give good results. I recommend marking the back of each chamber so that you know which fired which shot. Keep track of them (remember that Smith rotates counter-clockwise). Fire each shot from the six chambers and with either a full-size or reduced size target next to you, mark the position of each individual shot. Remember, concentrate on the bull as the aiming point for each shot. After two or three rotations you'll know whether the "flyer" is caused by a particular chamber. If not... you've got some other issues to check. But, you need to eliminate a cylinder that's drilled wrong, has a burr on the face or otherwise doesn't align with the bore of the barrel properly.

[Charles]

Here is the sum total of my knowledge on the subject at hand.

1. It is common for a revolved to have one charge hole that impacts a little ways from the other five.

2. Still, at 10 yards, all six should hold well within two inches.

3. YOu might have some kind of mechanical problem with the pistol, but it is more likely it is shooter error. I would not get concerned about it unless it continued to happen over several range sessions.

[Cast Bullet Hunter]

Here is the sum total of my knowledge on the subject at hand.

1. It is common for a revolved to have one charge hole that impacts a little ways from the other five.

2. Still, at 10 yards, all six should hold well within two inches.

3. YOu might have some kind of mechanical problem with the pistol, but it is more likely it is shooter error. I would not get concerned about it unless it continued to happen over several range sessions.

This is absolutely correct. Either mark the cylinder or see if there is a factory mark on the back, frequently there is, that will allow you to determine if it is consistently the same charge hole throwing the shot out of the group. If it is a fault with revolver it will always be the same charge hole, and always out in the same direction. Shoot at least 10-12 full cylinders before making a judgement. Shoot from a rest and at a reasonable range, say 50' or 25 yds. using your best trigger technique. Use a target that doesn't change shape when hit (like Shoot-n-See's) or change color or obviously show the hits. A plain black bullseye is best.

If the out shot is random, or is out in different directions shot-to-shot then the fault is in your technique or ammunition and not the gun.

[Old Time Hunter]

At ten yards I could throw the revolver and all the rounds would hit the same place. Seriously though, it is not uncommon to have one seem a bit off as your balance changes.

[Rusty]

Ask your local gunsmiths in your area to see if one of them has a "range rod" for .38 Specials. A range rod is a brass rod that is almost bore diameter. As you slide it down the bore it will enter the cylinder and you can tell if you have one hole that might be just a slight bit out of time. If you find one that's out of time it will hang up as it is about to enter the chamber. Check each chamber by going through them one by one.

[Leverluver]

I made the mistake iof buying a set of pin gauges so that I could know what all my chambers in all my revolvers were. Very disheartening experience. I did find out why some were more picky than others but all in all, they weren't "terrible". Also took a look at a 2nd generation Colt SAA being offered from an estate sale to see if I wanted to make an offer. I was very leary of a Colt in 44 Sp so took extra pains in measuring. One chamber passed a .431 pin. Another passed a .432 pin. Three others passed a .433 and one passed a .434. This all with a barrel with a .4269 groove diameter. I wanted it for a shooter and for that purpose, I wouldn't give 50 cents for that pistol. From the 50 or so cylinders that I have measured so far, I can say that uncommonality between chambers is the rule rather than the exception. The only one that I have measured that was near perfect (ironically) was a Uberti 32-20 SAA. All chambers were a prefect .313. Everything else was the wrong dimension for what is considered the "standard" bullet used or varied over .002" between chambers. Aint' life interesting

[J Miller]

Leverluver,

It's amazing that revolvers in general shoot as well as they do isn't it?

Joe

[1886]

Leverluver,

It's amazing that revolvers in general shoot as well as they do isn't it?

Joe

You said a mouth full! Linebaugh has some great thoughts on revolver accuracy. 1886.

[336A]

Thanks for all of the help guys I will get to the range soon and try again. As far as sending it back to S&W for repair goes I'm not so sure about that. I already had to return it once a couple months after I bought it NIB due to the barrel missing 3 of the 5 lands at the muzzle When I got it back from S&W whoever did the barrel replacement marred the finish on the left side of the top strap . As much as I hate to say it at this point I'm about ready to sell this item so as not get frustrated with the hit and miss Quality Control at S&W and use the $ to fund getting a USFA Rodeo in .38SPL. Anyone here have one of those in .38 SPL? If so how does shoot and how well are the sights regulated at the factory?

[TX Gun Runner]

I cut the forcing cones on these 2 guns and test fired guns with 20 rds only in each gun . These are loaded for FPS for SASS/CAS not for accuracy . The 2 guns below were a matching pair till I cut the one down .

[Griff]

Individual bore diameters in a cylinder don't mean a hill of beans where accuracy is really concerned. What is of major importance is that the centerline of each chamber is aligned with the centerline of the bore.

Sure, it will and can vary pressure a tiny bit as the cartridge expands to fill the chamber... but once that bullet leaves the case, it is the how that chamber aligns with the forcing cone that will aid or detract from accuracy. If the centerline is off in the chamber, it will cause the bullet to enter the forcing cone at a slight angle, and possibly remain cocked-eyed as it travels down the barrel. However, if the centerline is aligned with the centerline of the bore, even if slightly larger diameter it should enter the forcing cone straight and travel down the bore straight.

Leastways, that's my thinkin' on the subject.

[Old No7]

"Individual bore diameters in a cylinder don't mean a hill of beans where accuracy is really concerned."

Sorry, but I have to disagree with Griff BIG time on this one... See below for why...

"...if the centerline is aligned with the centerline of the bore, even if slightly larger diameter it should enter the forcing cone straight and travel down the bore straight if the centerline is aligned with the centerline of the bore, even if slightly larger diameter it should enter the forcing cone straight and travel down the bore straight..."

And therein lies the rub...

In my experience, most differences in cylinder bore diameters result in smaller diameter bullets skidding down the bore -- well aligned with the centerline or not -- thus causing much leading and resulting in wicked inaccuracy. (Once sized down by a too-small throat in the cylinder [one, or several as I saw on my Rugers], they won't auto-magically jump back up to bore size in the barrel.)

As backup to my thoughts on this, I'll repost the links to the cylinder throat & forcing cone work that I'd done on my Ruger .357 GP & SP series to optimize them for shooting lead bullets.

viewtopic.php?f=1&t=4317

viewtopic.php?f=1&t=4318

By the way, prior to that work being done, a "range rod" (a precision gunsmith's tool) confirmed the bores of the cylinder were very well aligned with the barrel, but the cylinder throats were undersized which didn't help the accuracy a bit.

Griff and I just may have to "agree to disagree" on this, and that's OK. I'm sure not trying to start a pi**ing contest, but I offer up my comments and posts to provide a differing viewpoint.

Tight groups,

Old No7

[Griff]

Nay, I don't think we disagree, as I agree with ya in the instance of a smaller cylinder bore than the rifling and forcing cone. Maybe to make my point clearer, I should've said, "... if the cylinder centerline is aligned with the centerline of the bore, even if the cylinder bore is slightly larger diameter it should enter the forcing cone straight and travel down the bore straight."

Where's that dern proofreader when ya need 'em?

[TX Gun Runner]

I send these 2 guns back to Ruger for repair . The cylinders where .426 and the barrels where .429 and wouldn't hit the broadside of a barn . They came back with .430 cylinders and are tack drivers now . These loads below are loaded for SASS/CAS fps and not target loads and this is a test fire target after cutting forcing cone to 11 degrees and the 1st time on paper in 14 yrs I own them . And the brass has been reloaded going on 80 times without one case failure and they are fired in 6 different guns . .