how to determine barrel bulges exist in m15-3 barrel?

[jrothWA]

shooting in a league, first and second weeks getting nice holes [sometimes where they are supposed to be], the past week, majority of impact are key-holing.

only thing I did was to clean the bore and cylinders.

Thanks for responses.

[ammo.crafter]

Need much more information.
Barrel crown?
Cylinder play?
New ammo?
Reloads?

[reddog81]

are you sure the bullet is keyholing? When using a target without a substantial backer the paper is much more prone to tear and can look like keyholing.

How would cleaning the gun cause a bulge in the barrel? Usually a barrel bulge is caused by shooting a round into a bullet stuck in the bore.

[jrothWA]

Crown good shape, bought LEO trade-in back in mid-90's,
using reloads for league shoot of :

Target @ unknown distance, exposed for 6-8 seconds, while I put r ounds on target, retract exposure for 5 seconds while I'll reload, then repeat for two additional time, repeat with two additional target pages.

required to use fmj or plated ammo.

[samsmix]

My personal 15-3 DOES have an almost imperceptible bulge in the barrel. Still able to shoot a "perfect" during annual qualification. No idea how it got there; happened before I owned it.

Best way to be sure is to get a micrometer and a copy of the original specs. Otherwise a trip to Smith. Does this gun see +P use? That's kind of a no no, and many fine pinned barrel smiths have been pounded loose by heavy +P use.

[Sevens]

I say there are two ways to find a bulge: first is to run your fingers carefully over the length of the barrel on the outside of the gun and feel. A more definitive way to send a rod and a jag and a tight-fitting patch down and feel the resistance in moving down the barrel -- and look for a spot where for just a bit, the resistance is gone.

I've come across three myself... two rimfire and one in a heavy barrel Model 10.

[b.thomas]

opps wrong post!

[SaxonPig]

Under good over head lighting hold the gun at eye level with the muzzle away from you and the barrel at about a 30 degree angle. You can usually see a bulge in the barrel this way. Can also run a tight patch down the the barrel and if resistance suddenly decreases then gets tight again it could indicate a bulge.

As noted it could be another problem. Inspect forcing cone for nicks, cracks and carbon build up. Check crown for nicks. Ammo? If reloads check bullet diameter. I always advise a good and thorough cleaning as the first step to resolving any gun malfunction. Amazing how often problems can be cured by cleaning.

My Victory Model in 38 S&W shoots 158 grain .357" fine through its .361" bore. But 190 grain bullets turned sideways. Go figure.

Note the hole at the bottom of the group showing the bullet in full profile as it hit the paper. Despite tumbling bullets the gun still made a pretty good group. Again, go figure.

[Driftwood Johnson]

Howdy

You say you are shooting in a league. Can I assume that means you are shooting at different clubs each week? Perhaps there was simply something different about the way one of the clubs hangs their targets.

I seriously doubt if you suddenly got a bulge in your barrel. As has been stated, the most common way to get a bulge is to fire a bullet into one already lodged in your barrel. Even then, it does not necessarily mean an end to accuracy. There is at least one old S&W M&P in my collection that has a bulge down near the forcing cone. Who knows when it happened, the gun is probably close to 100 years old. But the gun is just as accurate as when it left the factory.

Yes, to inspect for a barrel bulge you carefully run your fingers down the outside of the barrel and feel for a bulge. This method works best with a thin walled barrel, like the proverbial 'pencil barrels' of the older S&W revolvers. However the Model 15 has a relatively heavy barrel and a bulge may not telegraph itself to the outside of the barrel. The other thing you can do is peer down the bore with a really bright light. A bore light is not bright enough. Take an inspection mirror and shine the reflection of a bright over head light up the bore. A bulge will look like a halo in the bore. You should be able to see it.

Lastly, shoot the gun at paper targets properly set up on target backers, not free hanging targets without backers. If you see bullets impacting the target sideways, then you are key holing. A bulged barrel will not necessarily cause key holing. The bullet usually jumps right over the bulge without becoming upset.

This is what targets look like when bullets are key holing. I had an old Lee Enfield that simply would not put a good spin on bullets no matter what I did. I don't have it anymore.

[HiBC]

A bulge should show though to a micrometer or calipers.
I have found a visual bore inspection looks like a "ring" in the barrel.
As mentioned,determine if you really are getting keyholing

Then I might look to bullet size/fit.

And indexing/lock up.

Are you leading? Too small of bullets let gas leak past the bullet.The lead melts

If ,for any reason the chambers are not aligned with the bore,the bullet will be deformed.That can be the locking bolt and cylinder notches or damage resulting from flipping the cylinder shut.
A tool called a "range rod" is used to check that alignment.

[Jim Watson]

A guy here bulged the barrel of a M15 with ill advised loads. He discovered it when he cleaned the gun and felt the tight patch "jump" the bulge.

[buck460XVR]

required to use fmj or plated ammo.

Did the keyholing happen with plated ammo or one particular bullet? While you cleaned the bore, could it be lead fouled? Tumbling is just a result of a bullet that is not stabilized. Worn out or lead fouled rifling and undersized bullets are the most common reasons other than major barrel damage. My first thought would be to try a different bullet or up the charge.

[Don P]

Crown good shape

??
My Python has no crown and shoots fine

[Jim Watson]

Sure it has a crown. It just doesn't have the S&W convex crown or the "wok" crown so popular now with 1911 dressers. A flat crown is still a crown.

[rodfac]

he cleaned the gun and felt the tight patch "jump" the bulge.

That'll tell you if you have a bulge in the barrel at some point, but in reality, it's hard to 'bulge' a S&W bbl.
Back in the mid-60's I was the head range officer at the Air Force Academy's range. On the day in question we were introducing new cadets to the issue S&W M15, shooting 130 gr. FMJ, military, Remington ammunition. At the end of a string of 5 shots, one shooter raised his hand with a malfunction.

On inspection, we found a round nose 130 gr FMJ bullet sticking out of the muzzle and we couldn't open the cylinder. A faint like of copper showed in the gap, so the range gunsmith got a drift and tapped the protruding bullet nose back in, and down the bore til the one that was in the cylinder gap moved enough to open the cylinder.

As it turned out, we figure the new shooter had a squib load on the first shot, but being new, didn't know it. He fired the rest of the rounds pushing the squib down the bore til it protruded from the muzzle, all five of them!

The gunsmith tapped all of the bullets back down the bore and out through the cylinder opening, checked the bore, forcing cone and cylinders but could find no damage. I loaded all six chambers with rounds and shot a group that measured less than 3" at 25 yds. The gun was fine and showed no adverse effects.

We surmised that the cylinder gap allowed enough pressure to escape that there was no buildup in the barrel enough to bulge it. Smith builds some stout guns, but I'd not recommend a steady practice of continued shooting following a squib...LOL.

In the OP's case, if indeed he had key-holing, I'd suspect under-powered, low grade ammunition, or a severely damaged muzzle crown.

Rod