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To crimp for AR or not.

4xforfun said:
K...a little more info.....223 rem... 80VLD, 80.5, 85.5, 80 ELD, ETC.... in that 2400 - 2600 FPS range. I have quite a range of powders.....Benchmark, Varget, H335, H322, RL15/15.5/16/17 Not looking for speed. Looking to buck the wind and accuracy. I may even single feed them to negate the whole "fit in the mag" thing. 1-7 or 1-8 twist. 20+ inches
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Some like Varget but my favorite is 23.2 8208XBR behind a 77.

RL15 - good velocity with heavy bullets
H322 good accuracy at the cost of velocity.
Benchmark is similar to H322 in how it performs. Great powder for 52-55 grain loads
H335 is a good all around powder.
CFE223 - A good friend shoots a hot load of this behind 77s with success.

I've not tried RL15.5 but 16 and 17 are too slow.
 
When I started loading for AR's a friend strongly recommend it with the Lee factory crimp die, so I did so for a few years. About a year ago I ran some non crimped ones that I had loaded for my Tikka through one of the AR's & it shot better than any of my crimped loads. Did further testing & every AR shot the same loads better in crimped. He swore by it and it seemed to work for him, but not in mine.
So test yours, maybe yes, maybe no.
 
markm87 said:
I ran a bunch of crimp tests years ago. (My OTM/Target loads get shot in bolt gun and AR) Since I DO NOT anneal 5.56 neck (due to volume),I use the LEE Factory Crimp Die to somewhat unify the neck tension on mixed brass.

To my surprise, the first time I tested NON-crimped against Lee FCD crimped 77 gr OTMs, the Non-crimped group size was double that of the Crimped. At that time, it appeared that the crimp (as the ONLY variable in the test) improved consistency.

I repeated this test a few months back, and also included the Taper crimp as a 3rd variable. At that time, I could see no significant difference in accuracy in any of the 3 variables.

So at this point I still run a Light Factory crimp on ALL my 5.56 ammo, including single feed 88 gr ELDMs for bolt gun. The crimp most certainly doesn't do any harm in my process.

I just bought 2 more Lee FCD dies in 5.56 because they do wear out and stick after 20k or so crimps.
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I've had similar results from testing both crimped and non-crimped. I hypothesize it is varying years of LC brass aren't the same thickness and the 77 gr can actually lengthen when chambered resulting in COL variance of rounds once they are chambered. Before I started crimping I would find some round would be 5-10 thou longer than what they started at. I first noticed when I extracted a round and tried to reload it into the magazine to find it would no longer fit.
 
I played with crimping a long time ago. For me, the targets did not show that it helped. The chronograph did not show it helping either.

Even my full auto blasting ammo, which is cheap Hornady 55 FMJ bullets over cheap powder, dont get crimped.

My 223 Ackley coyote hunting ammo which is 69 gn TMK and Varget is not crimped either.

For my 300 Whisper/Blackout full auto blasting ammo, Gallant coated bullets and AA1680 I do crimp with the Lee collet crimp die. This is because of the lack of neck tension so I dont damage the bullet coating. But 300 Whisper isnt what you asked about.

If I thought it helped or could see where it helped, I would have zero problem doing it or recommending it.
 
4xforfun said:
K...a little more info.....223 rem... 80VLD, 80.5, 85.5, 80 ELD, ETC.... in that 2400 - 2600 FPS range. I have quite a range of powders.....Benchmark, Varget, H335, H322, RL15/15.5/16/17 Not looking for speed. Looking to buck the wind and accuracy. I may even single feed them to negate the whole "fit in the mag" thing. 1-7 or 1-8 twist. 20+ inches
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It's all fun, I learn't on a 6.8SPC forum how to "window" the front of a mag so you can run long over all lengths using the mag to get closer to the lands ....did a lot of single loading also.
At the time quite a few guys on that forum were seeking every bit of accuracy and fps/ft.lbs. out of that cartridge.
Awesome little round if you're looking for a bit more than a .223 or 5.56, good for hogs, deer, or SD
The crimp question came up a lot but the cannelures were never in the right spot for me...but some guys crimped a little bit...I tested and never found I needed to.
 
Depends on the caliber, bullet diameter, & bullet weight.... but many 223 types will get a light crimp, or no crimp depending on need, as seating and crimping are seperate for me these days.
The 450 Bushmaster gets a measured factory crimp... as much crimp as possible, and still head space correctly. And sometimes it gets a 454 carbide sizer for a bunch of neck tension on the lighter .451" dia bullets instead of. 452" dia., plus a heavier crimp, necessary for better ignition. As it will hang fire or stop powder ignition & leave bullet & unburned powder in the barrel, with these need high pressure and hard to ignite ball powders...it's better to stay with full diameter 240 gr and heavier bullets. But 240 to 500 grs is quite a large selection, and fits most needs.
 
I'm in the light crimp crowd as well, especially in an AR platform 5.56, or the 6.5Grendel, I use a LEE collet die that gives me about 2.5 to 3k neck tension, after seating my bullets I run them thru a factory crimp die that just kisses the neck! makes me feel better, is it necessary? maybe not but I still do it! in a gas gun, I still have very good accuracy doing this, my last Grendel loads shot a 7/8'' group @200m
 
My past experience is I noticed setback occur when a round was chambered on loads where seating depth did not result in full contact of neck with bullet bearing surface. If seated where entire neck had contact with bearing surface, no setback occurred when chambered. (.002 tension)

Does it affect accuracy? Well I noticed up to about .004 +\- setback, so if that difference in seating depth will effect your load, then there is your answer.
 
Cfshooter said:
My past experience is I noticed setback occur when a round was chambered on loads where seating depth did not result in full contact of neck with bullet bearing surface. If seated where entire neck had contact with bearing surface, no setback occurred when chambered. (.002 tension)

Does it affect accuracy? Well I noticed up to about .004 +\- setback, so if that difference in seating depth will effect your load, then there is your answer.
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If you are feeding from the magazine, consensus is to run.003 tension. If you are single loading by hand and pushing it into the chamber, Then you can run less tension.
 
4xforfun said:
Just like the title says......going to jump into the AR world. Do any of you guys crimp your loads? Is there two different "sweet spots" for crimped vs non crimped loads? Does crimping affect your accuracy....as in......"non crimped load shoots good, but after crimping not so much"?

Thanks,
Tod
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Tests have been done and light crimp is better than none. It gave lower ES and tighter groups. Not a huge difference but a difference. I crimp lightly with the Lee FCD. It does NOT raise pressures as many would think. It does raise initial pressure until bullet exits neck but nothing to worry about
 
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