jumping the crimp

[labnoti]

I had a couple rounds jump the crimp yesterday, and block the cylinder from rotating past the forcing cone. I'm new to revolvers, so I face uncertainty about how to prevent this. I'm using Berry's plated bullets that do not have a cannelure. The revolver is an Airweight j-frame and the load is close to standard pressure .38 Special. I crimp them with a roll crimp using a Lee Factory Crimp Die. If I recall correctly, the instructions suggest screwing the adjustment on the die down until it touches the case rim, and then screwing another full turn or more. I think I had it adjusted about 1 1/4 or 1 1/2 turn down from touching. The bullets that jumped were marked where the case was crimped, but not deeply. I've increased the depth of the crimp another half turn. I have experimented with cranking it even farther down, but with a non-cannelure bullet it just smashes a greater length of the case.

Those two failures were out of 300 rounds so far. I suspect I won't achieve excellent dependability with this bullet in this gun, but the bullet was selected only for training and I don't see a danger in using it for that purpose.

I also have Remington Golden Sabre bullets of the same weight which I intended to use for training and carry with a hot +P load. These have a brass jacket rather than copper plating and although they do not have a cannelure groove, they do have a lip. If I set the crimp in front of that lip, it should hold the bullet positively. I could carry Remington Ultimate Defense, the factory load that uses this same bullet if that was somehow more dependable. I'm concerned it may not be in a lightweight gun.

I am considering switching to an even lighter j-frame (11oz. vs 15 oz.) which will further exacerbate any crimp jumping problems. I should also mention I shoot mostly one-handed. I will shoot the rest of the Berrys and all the Golden Sabers I have in training by the end of this year. They were cheap at $0.08 and $0.14 per bullet respectively. I suppose I will find out after a couple thousand rounds whether the GS bullets can be depended on with this platform.

 

[Walkalong]

You could try a tighter sizer, or polishing the expander, but mostly you are asking a lot of a plated bullet in this application.

Pick up some Zero or Montana Gold JHPs in bulk and roll crimp them in the cannelure.

 

[labnoti]

It looks like the Montana Gold would be a better alternative to Berry's. I'll definitely get those next time, but they are not a bullet I want to use for carry. I also want to train with bulk of the same bullet I carry. The Golden Sabers might have worked, but I have some doubt now. There are other JHP's like the XTP and Gold Dot, but I also have a criteria that they expand at lower velocities from a short barrel.

 

[Walkalong]

I also want to train with bulk of the same bullet I carry.

Why? Train with a cheaper similar bullet loaded to the same feel.

 

[Toprudder]

I think a coated bullet with a crimp groove (not a cannelure) would work well. I generally prefer to crimp in a separate operation, but with crimp grooves, I set the seating die to crimp into the groove while I am seating.

Something like this: http://www.bayoubullets.net/38-357-158-gr-swc-1000-ct/

 

[labnoti]

Why? Train with a cheaper similar bullet loaded to the same feel.

Because it can expose problems like this one. I do train with a similar but not same bullet, like the Berry's. It's the same weight at least, but I found the plated bullet does not have anywhere near the same velocity as the jacketed bullet with the same powder charge. Had I not even begun to shoot a volume of the GS, I might have believed the plated bullet of the same weight would have the same velocity and point of impact. The Montana Gold would be more similar since it is also jacketed, but Midway is selling Golden Sabers right now for $0.11. Using a similar bullet in lieu of using the same bullet isn't necessarily a lot more attractive. Don't get me wrong though, I am not married to the GS or Remington Ultimate Defense. I found they expand dependably at the lower velocities from a snub nose and there are both factory defense loads and bullets for reloading available. I had to start somewhere. The Berry's have failed as a good substitute bullet, but I will still shoot the rest of a thousand very cheaply. I have a couple thousand GS, and I would buy more now at the lower price if I knew they wouldn't jump. But I've not come to that conclusion yet because I've been shooting a cheaper similar bullet instead of the same bullet.

 

[Ruger 15151]

It's the same weight at least, but I found the plated bullet does not have anywhere near the same velocity as the jacketed bullet with the same powder charge.

Less velocity may be due to the fact that Berrys bullets are oversized. For example, most 9mm FMJs are consistently .355 in diameter where many plated 9mm bullets ( including Berry's) are between .356 and .3565. They can be more accurate under 25 yards in oversized barrels. However, if your barrel is closer to Sammi specs and you are loading an oversized bullet, you are going to need a hotter load in order to see the same velocity.

Try working up a different load for the plated bullets and you will likely see you accuracy come back.

 

[243winxb]

Mixed brass/range brass?

https://www.thehighroad.org/index.php?threads/light-weight-snub-crimp-jump.799171/

 

[brewer12345]

I would plump for cast bullets for target and training.

 

[santacruzdave]

What about training with inexpensive bullets, and testing your defence loads to make sure they function as required? You could train using a ratio of inexpensive to your fav defence projectiles of say 80/20 or the like. Or if $$$s are no object, you can shoot exclusively with your defence projectiles. I get a good solid crimp using coated lead with a crimp groove and a Lee factory crimp die in my revolver rounds. Happy reloading in any event.

Have fun and be safe!

 

[Walkalong]

Because it can expose problems like this one.

?? Ok then.

 

[Walkalong]

Have fun and be safe!

Yep.

 

[243winxb]

. I'm new to revolvers, so I face uncertainty about how to prevent this.

You could try a tighter sizer, or polishing the expander,

Like Walkalong said. More neck tension is needed. The expander needs to be .002" to .003" smaller then bullet diameter. But first the sizing die has to do its job, make the brass smaller.

Measure the case neck before and after seating a bullet. After seating, the case should have expanded a minimum of .003" for correct neck tension.

A very soft plated or lead bullet may be compressed by the brass on seating, resulting in light neck tension. Not good.

It has been said a Lee FCD may post size the loaded round, resulting in the lose of neck tension/bullet hold. https://leeprecision.com/reloading-dies/hand-gun-dies/lee-carbide-factory-crimp-die/

My S&W 337PD 38+P has a warning not to use lead bullets. I think this would apply also to soft plated bullets? This is to keeps bullets from jumping crimp.
But all i shoot is my home cast lead. On bullet seating , my brass expands .003" , providing enough neck tension/bullet hold.

 

[labnoti]

Less velocity may be due to the fact that Berrys bullets are oversized.

The bullets, Rem GS and Berry's plated are both 0.357", but the Berry's has a bearing surface about 0.30" inches long while the GS bearing surface is only about 0.15" long.

If I look at Alliant's book, they show an unspecified cast bullet achieving a slightly greater velocity than jacketed with the same powder charge and only slightly more OAL. I would think additional OAL would lower pressure. I'm not sure why Alliant's data looks this way:


38 Special 125 gr JHP Federal 1.42" 6 Fed 100 BE-86 5.4gr 1,002fps
38 Special 125 gr Cast RNFP Federal 1.46" 6 Fed 100 BE-86 5.4gr 1,023fps

 

[murf]

you could always reduce the powder charge and crimp on the ogive. the powder reduction is because you will have to seat the bullet deeper to place the crimp on the ogive.

luck,

murf

 

[243winxb]

I'm not sure why Alliant's data looks this way:


38 Special 125 gr JHP Federal 1.42" 6 Fed 100 BE-86 5.4gr 1,002fps
38 Special 125 gr Cast RNFP Federal 1.46" 6 Fed 100 BE-86 5.4gr 1,023fps

Less friction from lubed lead bullets produces higher velocity, would be my guess.

 

[Vern Humphrey]

Check for grains of unburned powder. If you're getting bullet creep, clearly your crimp is not doing its job. That may mean there isn't a good pressure spike because the bullet is moved too easily, resulting in incomplete combustion of the powder. Lower than expected velocity might be an indicator of that.

 

[Blue68f100]

If your using mix brass, is it just 1 mfg that's causing the problem. RP was know to have thin soft necks which often lead to reduced neck tension. The mith buster showed that things have changed over the years depending on mfg. Problem still exist though. All it takes is tolerance stacking on your dies to create a problem with thin wall brass, or under sized bullets. I would suggest reducing the expander size to increase neck tension. Adding more crimp can cause issues, if your already applying a heavy roll crimp. You sould have 0.002"-0.003" neck tension. Shoot of the heavier neck tension, and try not to expand the full length. You only need to expand enough for the bullet to set on top and not shave when it's seated.

 

[Toprudder]

If possible, use a 9mm expander for 38/357. It should give slightly more neck tension.

 

[labnoti]

Right. I understand if the bullet is seated so it's nearly touching the lands in front of a rifle chamber, the pressure spikes because of the resistance of the lands. It doesn't seem to my inexperienced self like a crimp on a soft brass case could hold the bullet firmly enough to build significantly more pressure, but I wouldn't dispute that it's certainly possible. I don't think I would even need incomplete combustion, but only less area under the pressure/time curve to see lower velocities. If the crimp is helping build pressure, that would explain why the jacketed bullet is realizing higher velocities, simply because the plated bullets have the worst crimping conditions: soft metal and no cannelure or groove. The plated bullets can just slip out.

This has been a valuable discussion to me. As I mentioned, I'm considering switching to an 11 oz gun. I shoot one-handed. They will be ideal conditions for this problem to occur. I'm going to need to select a bullet and crimp that is resistant. I've also decided to reconsider my goal to achieve reliable hollowpoint expansion because the hot loads needed to do it slow down shot strings and exacerbate things like crimp jump in a light gun, and I've come to the conclusion it is more important to focus on penetration than expansion with lighter loads.

 

[Steve C]

On the rare occasions when I have had bullet jump simply re-crimping the remaining unfired ammo increasing the crimp has solved the problem.

With plated bullets from Berrys or Ranier I use a dedicated taper crimp die for the 9mm and 38 calibers by Hornady that works well holding non cannelur bullets in place. With Remington Golden Sabers a roll crimp where the case mouth meets the edge of the bullet above the driving band with seating depth matching factory ammunition has been adequate for both the .38 spl and .357 mag.

 

[jak67429]

I'm using Berry's plated bullets that do not have a cannelure.

This is your problem. when you crimp a bullet without a crimp grove you squish the bullet. this also causes the case to lose neck tension.