Crimping Rifle Bullets

PaulS · Posted: Wed Dec 05, 2018 8:04 pm Post subject: Re: Crimping Rifle Bullets

Aloysius, I only anneal my cases when I feel the need. I only partially size the necks so they fit the chamber well and center both at the front and rear. Except for the semi-autos, I do full length size those cases.

hunterjoe21 · Posted: Sat Dec 08, 2018 5:12 pm Post subject: Re: Crimping Rifle Bullets

Dies have been received.Now I need to clean off the bench...

The Lee instructions for setting the dies are vague at best. Anyone have suggestions or tips/tricks on set-up and what to do/not do with them?

Oh yeah... GO ARMY

slimjim · Posted: Sat Dec 08, 2018 6:02 pm Post subject: Re: Crimping Rifle Bullets

slimjim wrote:

Good you got the dedicated Lee FCD. No need to be in the cannelure. In my .270 Win, crimping did not increase neck tension but did reduce variation in tension by 50% - measured with a force gauge pulling bullets. I use a medium crimp, e.g., 0.003" indent in the brass (collet pedals not touching).

It wouldn't be wrong to reduce your powder charge but you are already 1.5 grains below max. I would crimp and go.

I run the blades of the caliber into the groove left by the crimp and compare it to the neck diameter. Mine is about 0.003" less. I even do it for monolithic bullets but it takes a bit more pressure on the lever. You really can't do to much with a lead-core bullet. Maybe start by screwing down the barrel of the collet so the gap in the collet is about half what it is when open and turn down from there.

Or ... run your ram full up, screw down the die until it touches the ram, they continue to turn as your watch the collet petals close.

I don't remember following the directions.

hunterjoe21 · Posted: Sat Dec 08, 2018 6:55 pm Post subject: Re: Crimping Rifle Bullets

Thanks Slim.

I don't always FOLLOW the directions, but I do always READ them.

I watched a few on-line videos, so I at least have a better understanding of the die function. I didn't realize that the shell holder is what actually forces the collet up in to the die body, forming the crimp. Makes sense if you think about it.

I have plenty of unfired .300 Win Mag loads. I'm gonna crimp 10 of them and see if my accuracy is affected.

Prolly try the same for the .270, just cause...

slimjim · Posted: Sat Dec 08, 2018 8:48 pm Post subject: Re: Crimping Rifle Bullets

Your loads will be affected because you likely tuned them for no crimp. They may get better or they could get worse. Start with light-medium crimp initially. If they groups get worse, decide if you want to retune or wait until you develop your next load and use right out of the box.

To get more neck tension on my 6.8mm, I went down 0.001" on my bushing and the groups went south. went back to original bushing and started crimping and all was well.

Hope all goes well for you.

Bushmaster · Posted: Sat Dec 08, 2018 8:58 pm Post subject: Re: Crimping Rifle Bullets

If the field is knee deep in mud I'll bet on the Army. But if the field is waste deep in water I'll go with the Navy.

Elvis · Posted: Sat Dec 08, 2018 9:08 pm Post subject: Re: Crimping Rifle Bullets

and you wait for the air corps when??????.....or are you ALWAYS going to be waiting if you call up for air support???

slimjim · Posted: Sat Dec 08, 2018 9:12 pm Post subject: Re: Crimping Rifle Bullets

Elvis wrote:

are you ALWAYS going to be waiting if you call up for air support???

Not if you call for me!

Bushmaster · Posted: Sat Dec 08, 2018 9:30 pm Post subject: Re: Crimping Rifle Bullets

If I call for air support it will be Naval Air.

slimjim · Posted: Sat Dec 08, 2018 9:32 pm Post subject: Re: Crimping Rifle Bullets

That's me! Go Navy! Beat Army (next year)!

hunterjoe21 · Posted: Sun Dec 09, 2018 8:11 pm Post subject: Re: Crimping Rifle Bullets

I made some room on the bench this afternoon. I segregated 20 rounds from the remaining ammo I had assembled for the .300 Win Mag to use as a test and crimped 10 of them, using Lee's suggestion of 1/2 turn "down" after the collet contacted the shell holder.

My thinking is I'll fire 1 three round group of non-crimped followed by a three round group of crimped and compare the initial results. Repeat if warranted. I want to keep the same 3 rounds in the magazine during each test, ultimately leaving me with 3 crimped and 3 non-crimped that have had 6 rounds fired "above" them. In my simple mind, the real test will be comparing the final groups which will determine whether mashed tips and crimps make a difference in the original loads. None of it will matter though if there is a significant negative impact to group size during while performing the first part of the test. In that case, I'll need to go back and "tune" my load development using the crimp.

Make sense?

Elvis · Posted: Mon Dec 10, 2018 12:00 am Post subject: Re: Crimping Rifle Bullets

sure does Mate...for what its worth one of the longest shots Ive ever pulled off was at a chammy/chamious who was standing on a rocky point,first shot clipped her toenails giving me correct Kentucky windage,2nd shot struck true so about 24" projectile drop for .270 winchester 130grn factory load with the big soft lead tip nipped off with sissors!!!! it didnt effect accuracy at all,at least on a horizontal plane anyway.

hunterjoe21 · Posted: Thu Dec 20, 2018 11:12 pm Post subject: Re: Crimping Rifle Bullets

I'd say that my initial test was inconclusive, mainly due to me having a "bad" day behind the rifles again. The groups fired without the crimp (control group) were worse than normal, so I gotta take the blame.

The .270 crimped groups were slightly worse, while the .300 Win Mag were about the same as the control, except for one. I don't know if I found the "zone" suddenly or it was a fluke, but I fired the best group ever from this rifle.

I have more bullets, plenty of primers and powder, and cleaned brass, so I'll try it again. I might increase the round count though.

slimjim · Posted: Fri Dec 21, 2018 7:50 am Post subject: Re: Crimping Rifle Bullets

hunterjoe, you are getting some good recoil therapy. I don't look for any differences in accuracy. I just make crimping part of the process and develop loads from there.

English Mike · Posted: Fri Dec 21, 2018 2:15 pm Post subject: Re: Crimping Rifle Bullets

slimjim wrote:

hunterjoe, you are getting some good recoil therapy. I don't look for any differences in accuracy. I just make crimping part of the process and develop loads from there.

If nowt else, it removes one variable from the process & that can only be a good thing.