Crimping LRN 9mm bullets...

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bflobill69

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I recently picked up 9mm dies for my Dillon RL550B. Had no problems loading Winchester 115gr FMJ bullets.

Love this new press, its an absolute dream to use.

I did however have real difficulty getting these 115gr LRN bullets to crimp and seat properly. When checking in gauge they were WAY OUT, and no matter how tight I crimped em they would still move in case.

It seemed that I was eventually crimping them so much they might have had excessive breach pressure (had they even been able to be chambered, which they were not).

I noticed that the FMJ bullets I have been loading are .355 diameter, while these LRN are .356...

I mainly load ammo for revolver(.38/.357 and .45LC), so loading semi-auto cartridges is relatively new to me.

Anyone else had difficulty with LRN bullets in 9mm? :(

Bflobill69
 
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Are you roll or taper crimping? I loaded a lot of LRN (w/taper crimp) for a TZ-75 a few yrs back, and had no troubles.

Larry
 
You don't set bullet resistance with crimp, neck/case tension decides that.
A taper crimp just needs to remove the bell you put in with your expander die and a slight amount more so it will feed reliably, depending on the firearm. As you found, no amount of extra crimping will make the bullet tighter in the case.

Since lead is normally larger diameter than a fmj and they aren't making it through your gauge, I'd say you need to shorten them up until they make it through.
Since you are going to be shorter, working up from a minimum load is a given.
Which leads to:
Seating depth(Amount of projectile contacting surface inside the case.) might have something to do with the problem of them moving easily. Being lead is likely to be denser than the fmj and if you are seating to the same O.A.L. there will be less bullet inside the case. Shorter O.A.L. will probably solve that issue also.
 
crimping and swedging-- samething

I just found the same problem. For accuracy you need -.356,
.357, .358 depending on your barrel. Pull a couple of your bullets and see what they now measure. Over crimping may have you down to .352. All you will get is a leaded up barrel.
My new dies seem to be roll crimp, and the lead will spin in the case but will not push or pull. Seemed to shoot ok. be sure to use your barrel as a test gauge when checking . When I got to the range my test gun shot nice. My others seem to have tighter chambers. Not all the same. Damn Smith's, couldn't make'm all the same.
Mike.
Ps. you can swedge copper jacketed down also by over crimping.
 
:) All ammo that is reloaded for a semi auto handgun has to be taper crimped because the bullet head spaces on the case mouth. If you have a cannelure you shouldn't crimp on it. One way to see if you have enough crimp is to take the barrel out of the gun and insert a loaded round into the barrel. Push as hard as you can with your thumb and turn the barrel upside down. If it falls out freely you have the right crimp. If it sticks you have to much crimp. If you have to much crimp the bullet can go to far into the barrel and you will have light strikes on the primer or no primer contact at all. Also if you don't have enough crimp the shell may not drop into the barrel freely. There is a fine line on getting the right taper crimp. As for the lead bullet being one thousandth bigger than a FMJ bullet that is normal. I have loaded many thousands of lead bullets for semi auto pistols over the years so don't go buy the more expensive FMJ bullets. Don
 
I am envisioning a lube groove and a crimp groove but a cannelure?
 
When I started reloading for 9mm, I found that setting the belling (expander) was very critical. It look a lot of trial and error to get it just right. Once I got it right, it was easy going.
 
BE Mike said:
When I started reloading for 9mm, I found that setting the belling (expander) was very critical. It look a lot of trial and error to get it just right. Once I got it right, it was easy going.
Click to expand...

I don't understand why belling is so critical. I try not to over do it because if you do it to much it will wear the brass out. Normally I bell the case so I can set the bullet in there with no problem. It's setting the taper crimp that I find is critical. Don
 
Will seating these LRN bullets deeper than the FMJ 115gr bullets cause failures to feed? It would seem seating them deeper would solve my current problem, but also will increase breach pressure ALOT.

I am not a BIG semi-auto shooter so please forgive my lack of knowledge here. And TY again for all the responses!

Perhaps I should STICK to factory ammo =/ Bah what fun would that be?

Here are the bullets to which I am referring. Its a crimp groove, not a cannelure.

LRN9MMRN2.jpg
 
That looks more like the lube groove to me. Your case OAL should be the determining factor during seating. Crimping shouldn't change case OAL.
 
Not a crimp groove. It is a grease/lube groove. Since those are bear creek black bullets(pre-lubed moly coated) pretend they aren't there.

Make a dummy round with no powder, start at your beginning O.A.L. saami max length is 1.169 for 9mm. Keep moving in a little at a time until your round fits your barrel and passes the plunk test.
Check with your case gauge to see if there is a headspace issue then. It is not likely a headspace issue, the bullet is(was) likely hitting the rifling in the barrel. When it slips in and out of your barrel with no help you will know the O.A.L. your gun likes, as long as they fit in and feed from your mags you are good to start up a load(Remember the light taper crimp.).
Published lengths and all that looks good in the book, but if it doesn't work in your barrel it is worthless.
I always ignore that part and figure out what my guns like.

As always, one starts at the minimum loads and works up.
Be safe, have fun.
 
HAWKEYE10 said:
I don't understand why belling is so critical. I try not to over do it because if you do it to much it will wear the brass out. Normally I bell the case so I can set the bullet in there with no problem. It's setting the taper crimp that I find is critical. Don
Click to expand...
Setting the crimp has never been a problem for me. I used the case mouth measurement that I found on factory ammo. Belling the factory new Starline brass, I found that if the belling adjustment wasn't done so that there was just the slightest bell that the fmj bullet would drop down into the brass and of course if there wasn't enough belling the case would be crushed. I never had this happen with .45 ACP brass.
 
After quite a bit of fine tuning (seemed like 3-4x what it takes me to set up for revolver loads), I think I got it. Basically OAL for these LRN's have to be ALOT shorter than on the FMJ's. Thankyou all for your suggestions!
OAL for my FMJ loads are app: 1.156
OAL for these LRN loads were app: 1.109 - considerably shorter... So off to the range tomorrow over lunch to see how they perform.

LRNVSFMJOAL.jpg
 
Last edited:
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Looks good. :)

That rounded profile was what was catching you up. They don't have the classic parabellum profile that can go a lot longer before touching the rifling.

Let us know how they shoot.
 
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