ar-15 reloading question

smak_daddy

smak_daddy

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i have read some articles that talk about how the violent stop and go motion of the action can slide the bullet into the brass further, or even yank it out on stopping.

Is there an easy effective solution to this?

I am an experienced bolt rifle reloader. I have not reloaded for semiautomatics.

If it matters, I plan on using 77 gr SMK and Varget powder in a Stag model 4R 1:7 twist.

Thanks in advance for any advice.
 
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The Lee "Factory Crimp Die" will crimp any normal bullet. If you want to use the crimper that came in your seating die, you need to have some sort of groove to crimp into.
 
smak_daddy said:
I heard you could only crimp bullets if they were cannelured.

If I can crimp my match kings I am in business.
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I use a .223 taper crimp die for non-cannelured bullets. Works well in my AR with 68 gr. HP BT's.
 
smak_daddy said:
have you noticed if crimping hurts accuracy at all?
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get ready for a deluge of opinions on that subject. :eek:

Cannelure or not, the Lee Factory Crimp Die is supposed to "make its own groove". However, in my limited experience, it can negatively affect bullet hold overall in hard/poorly tensile brass. A correction for this is use soft brass or anneal the harder brass.

The reason they recommend crimping for autoloaders is the fact that when the bolt picks up the round, there is a chance that the bullet will sink into the cartridge during the sudden forward motion. When the bolt shoves the cartridge into the chamber, the momentum could cause the bullet to seep out of the case mouth, or worse, contact the rifling or even worse, leave the case entirely :(

Crimp advocates will tell you that the crimp will increase bullet hold in the neck (which in proper conditions is likely true), and the bullet will start to travel forwards at a more uniform pressure. This would in theory lead to better accuracy.

I don't know what true no-crimp advocates would tell you, because the only ones I have ever met don't really know why they do not crimp, they just don't :rolleyes:

I only use bolt actions for what I reload for, so I crimp with my crappy brass (annealed), and I don't for my softer high-quality brass. Either way, accuracy seems good but I am not trying to put every one in the same hole ;) For hunting, or any application where I am not feeding the cartridge with velvet gloves, I would crimp.

But as I said, I am no expert. So far my reloads have been satisfactory, and I have been confident that they were safe.
 
Are you having problems now?

Most FL sizing dies, give quite a bit of neck tension. That is usually enough to hold a bullet in place.

Simple test. FL size a case, seat a USED primer, fill with an equal weight/volume of salt/sand as your load, seat a bullet.

Run this 'cartridge' through your action at least 5 times and see if the bullet moves at all. If there is no movement, you are ok with loads that go bang.

I have limited loading experience for the AR but never had to crimp. I have loaded quite a bit for the M305 and never found a need to crimp.
Jerry
 
I crimp to keep the bullets from getting jammed further into the case as they climb the feed ramp, preventing pressure spikes (least worried) or feed jams in the rifle (crap!)
All of my load development with match bullets has not benefited in accuracy from being crimped.
I have a pile of 62 grain fmj (thanks again Barney) with canalures that do benefit from being crimped.
 
Alternatively, you could machine (drill and emery cloth) a tiny bit off of the expander ball (reduce the diameter) in your sizing die. That will hold the bullet a bit tighter.
 
agilent_one said:
Alternatively, you could machine (drill and emery cloth) a tiny bit off of the expander ball (reduce the diameter) in your sizing die. That will hold the bullet a bit tighter.
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Maybe, maybe not. Precision Shooting ran an article from a guy who tested hold strength for different grips. He found that .002-.003 difference between the bullet and neck gave the best grip. Below that - as in .004 and up - the grip lessened. Likely explanation - in the .002-.003 range, the brass is still elastic. Past that, and you're into the inelastic range and the brass deforms instead of gripping.
 
acrashb said:
Maybe, maybe not. Precision Shooting ran an article from a guy who tested hold strength for different grips. He found that .002-.003 difference between the bullet and neck gave the best grip. Below that - as in .004 and up - the grip lessened. Likely explanation - in the .002-.003 range, the brass is still elastic. Past that, and you're into the inelastic range and the brass deforms instead of gripping.
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You may well be right, as I have never tried reducing the size of my expanders. Maybe one of these days I'll have to give it a go - just for interests sake.
 
mysticplayer said:
Simple test. FL size a case, seat a USED primer, fill with an equal weight/volume of salt/sand as your load, seat a bullet.

Run this 'cartridge' through your action at least 5 times and see if the bullet moves at all. If there is no movement, you are ok with loads that go bang.

Jerry
Click to expand...


That sounds like great advice!
 
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