Bullet Pull-Interesting Experience

[Ben_hutcherson]

I had my first experience with bullet pull at the range the other day, and am a bit at loss for how to explain what happened.

I was shooting a 4" M&P in 38 Special-this is an all steel gun, and not exactly lightweight. The load was 3.2gr Titegroup under a 125gr cast bullet. I find this to be a fairly light recoiling load in general.

When I load, I flare the case just enough to seat the bullet without shaving the base. With target type loads, I then roll crimp very lightly into the bullet crimp groove of cast bullets.

I shot about 300 of this round at the range the other day(split evenly between a 4" and 6" M&P) and only experienced bullet pull with one round out of the 300.

What happened was that I fired 5 rounds, only to find the gun locked up for the 6th round(hammer would not cock, cylinder would not swing out). After fiddling with the gun for a few seconds, I pulled the hammer back to the half cock position and rotated the cylinder backwards to allow me to open it.

Upon dumping the cartridges, I found that the "pulled" bullet had come completely loose from the cartridge-i.e. the bullet stayed in the chamber throat and the(unfired) cartridge and powder dumped out on the bench.

Any thoughts on why I would have this problem with 1 out of 300 cartridges-especially considering the light load and "normal" weight gun?

 

[scooter123]

My hunch is that you managed to get an unsized case mixed into your sized cases. The resulting lack of neck tension would make it very easy to have the bullet pull in spite of being crimed. Another option is that the case may have split but I would have thought you would have seen that.

 

[Ben_hutcherson]

I don't think an unsized case is possible, as I resize and deprime in the same step and thus couldn't have primed the case without it being resized.

I kept the case separate...I don't recall noticing a split, but it's certainly possible.

 

[Jellybean]

Possible causes are: Dies not adjusted to give enough neck tension/bullet crimp.

Short stroking the lever and not getting the bullet crimped properly.

Cases not all the same length and the shorter ones not getting proper crimp.

 

[MichiganScott]

It's possible you missed one if you crimp as a separate step.

I would have actually guessed an unsized case, but you claim it's not possible.

 

[Ivan the Butcher]

I see why you ruled the un-sized case out, and I agree. A small possibility is a under sized bullet. Sometimes when casting a too quick pour will leave a bullet that looks fine but is about 8 thousandths small in diameter. Depending on the lube and size system you use this can end up in a loaded round and not have enough neck tension to remain seated during recoil. Ivan

 

[11e40]

what brand of dies are you using? I had this happen with a set of lee dies. they would not size the case to allow proper neck tension. hth.

 

[venomballistics]

Cast 125 grain.
Could be a grossly undersized bullet.
Dropped size can be kinda wild if the mold and lead temps get out of a nice even keel.
If it's a Lee mold they are notorious for dropping a little smaller than most others.

 

[Ben_hutcherson]

I am using Lee dies. I have loaded probably 4000 rounds of 38 special with this set, and this is the first issue of this sort I've had.

At least on target loads, I seat and crimp in the same step, so don't think I could have missed crimping. I load on a single stage press and inspect all of my loaded rounds in a loading block, so feel like I would have noticed a bullet not fully seated.

As for the bullets-they came from a small, local commercial caster(I did not cast them myself). I've generally had good luck with them, although that doesn't mean that all of their bullets are perfect. I saved the pulled bullet, so will measure it and report back.

 

[venomballistics]

Back when I cast for profit, most people would have loaded most of the rejected slugs I just remelted.
Take a picture of the offending bullet, cleaned of lube.

 

[ironhead7544]

Could be a short case. Also, you will find out of spec bullets and cases. I like a bullet with a deep crimp groove, like on the Keith bullets. And a good crimp. I dont like problems at the range. Could spoil your whole day.

 

[H Richard]

There is a distinct possibility of a short case. I did find one, nearly .040" short, a 44 Special brand new Winchester case.

 

[dla]

--snip--
With target type loads, I then roll crimp very lightly into the bullet crimp groove of cast bullets.

--snip--
Any thoughts on why I would have this problem with 1 out of 300 cartridges-especially considering the light load and "normal" weight gun?

Yea, you screwed up. You didn't check for bullet movement to make sure your reloading process worked for your application. Hint - consider using the Lee FCD for your crimping as it doesn't rely on trim length for consistent crimp.

 

[scooter123]

These are reported to be light recoil target loads by the OP, IMO without any crimp at all they shouldn't pull in a K frame. I think the only potential cause is a lack of Neck Tension, which does at least 80% of the "work" in retaining a bullet in a handgun load. As for causes, there are just three that I can think of, 1) and unsized case (pretty well elminiated by the OP sizing and depriming at the same time), 2) a split case (no report on that yet unless I missed it), or 3) and undersized bullet. Since the bullet came from a small independent caster local to the OP my vote is on an undersized bullet. Lets face it, a home caster probably won't have the money or inclination to use an automated sizing line or employ the Quality Control Procedures of a major bullet manufacturer.

 

[Ben_hutcherson]

I appreciate all of the input. I'm really leaning toward it being an undersized bullet.

Even if the case were short, as mentioned it should still have roughly the same neck tension or possibly even more since it would have been expanded less.

I really don't feel like it was a split case. I hadn't segregated the case(as I intended) but have been through most of the brass from that range trip and haven't yet encountered a split case.

The slug is at the bottom of my ammo box, but once I dig it out I'll clean it up and measure it against others from the same lot(I still have over 1000 of them).

And, as I mentioned, this was an all-steel K frame shooting a light target load, and happened with 1 round out of 300.

 

[dla]

I appreciate all of the input. I'm really leaning toward it being an undersized bullet.

I guess I'm curious why you believe it is OK to have a loose roll crimp? This is a basic Revolver reloading step that should not be skipped over in this discussion.

Yes, you may have had an under-size bullet, but I doubt it because casting alloys are done in batches and making one high-shrink bullet is sort of weird. Ugly bullet yes, skinny bullet no.

My guess is that you've always had some amount of bullet pull going on and you've just never checked for it. Yes, the 38spl is a weeny round. Yes, the K-frame is a weeny pistol. But bullet pull isn't based on our perceptions - it is something we need to verify. Ditto with setback in autoloaders.

So IMO, you need to rethink your crimping process.

 

[Ben_hutcherson]

I dug the slug out of my range box, cleaned it off, and here's what I found:

I measured a dozen unloaded bullets from the same lot, and found that they measured anywhere from .3578 to .3582.

The offending bullet measured .3567, +/-.0001"(I took several measurements at several different points around the perimeter). Looking at it closely, the driving bands lack the sharp edges of other bullets from the same lot, making me think that it probably slipped through the lubrisizer without being sized.

Here are some photos-the "bad" bullet on the left, and the "good" bullet on the right.

I'm also including photos of a couple of loaded rounds from the same lot.

I took down one from this lot, and it took a good "whack" with the inertia puller to even get the bullet to start to move-far more than what I felt under recoil.

 

[venomballistics]

Little fuzzy, but the bad actor looks like a fill out issue.
Looks rounded at the base of the groove.
These often drop small.
If you get into casting, sort those out for re melt.

 

[Ben_hutcherson]

Sorry for the bad pictures, but the suspect bullet does indeed have a different look from the rest of the bullets.

 

[venomballistics]

Pic might leave a lot to be desired, but it is good enough to show the problem.
In my early days of casting, I never had a pull issue with those.
I did, however, have accuracy and leading problems, and learned to watch for those.
Your dies must be right on the fringe for this to happen, but the ammo works for you till you hit a bullet that won't work anyhow.
Other than a little inspection work to avoid these under filled bullets, you need not change anything.