Reloading for 5.56 AR-15----Crimp or No-Crimp?

[Sniper Uncle]

Forgive me if this has been discussed ad-nauseam.
I did a search on this question, and immediately came across two different theories as an answer to this Question.

Let me back up a little. My wife has a S&W M&P-15 in 5.56, and I have bought about 2000 rounds of once fired military brass. I have a swager, and do care for the primer pockets, so I don't need advice there in the context of my question here. I am currently working on some loads based on Chris Long's paper on OBT. They are 55gr Hornady A-max, 26.1 grains Varget, at standard seating depth, with CCI primers seated just below flush.
QuickLoad says this is a compressed load, by almost 13%, but I disagree a little there, as the powder only reaches the bottom of the neck, (I charge from a RCBS Powder Dump, checking ever 25th round---never seems to be more than a kernel off, and I tap the case gently on the bench to settle). I read an article on the internet about acceptable compressed loads, and how to tell if they were too tight, and also, QuickLoad takes into account compression when showing pressure curves. In this article, they said to load some test loads, un-crimped, and check the seating depth after loading, about 10 minutes later, and the next morning, and see if the bullets have sprung back out at all. If the bullets haven't moved, they should be good to go. According to this test, there is no problem with powder capacity in my loads, as the un-crimped bullets haven't moved and it is several days later.

We have shot quite a number of the same recipe, only 26.0 grains Varget, not 26.1, and no undue pressure signs, nor have the bullets moved at all, even uncrimped.

So, having said all that, can any of you weigh in on the question----Crimp, or No-Crimp? Please give me reasons or experiential knowledge to back your statements.

Thank you so much,

 

[Sniper Uncle]

Thoughts, anyone? Thanks,

 

[sierracharlie338]

Hell I'd like to just be able to put some hands on some small base dies!

 

[gixxer822]

i load by a simple rule. semis get crimped unless being single feed, and bolts uncrimped. seems like your running a lil hot so id crimp as light as possible cuz it might give u pressure issues. or maybe even drop the load and work back up to the 26 or 26.1. better safe then sorry. cannelure or not a light crimp will not destroy the bullet. and since your shooting 55gr bullets im sure your not shooting LR

 

[AnthonyL]

Same, all semi-autos get a crimp from the Lee Factory Crimp die. With semi-autos the there is the opportunity for set-back while the round is stripped from the mag by the bolt and placed in the chamber. If this happens you have a kaboom on your hands.

Bolt action or anything single shot gets no crimp.

 

[insight3b]

I take a loaded round an jam it bullet first into the edge of the bench. If it moves slightly under moderate pressure I crimp. If it doesn't move then neck tension alone is enough. All long term storage/shtf ammo gets a slight crimp.

 

[Sniper Uncle]

Maybe I should add, I tried to pull a bullet using a kinetic bullet puller. I had to really smash the hammer about 15 times to get the bullet to move. I'll also check some rounds at the range that have been chambered to see if the bullets have moved at all. It takes quite a lot to move these bullets at all, uncrimped...

 

[zacii]

I load 55 grain BTs over Benchmark powder. It's not a hot load, about in the middle between min and max with my data.

I don't crimp and I haven't had any problems.



Sent from my Galaxy S2

 

[1lnbrdg]

I normally burn out 1 ~2 barrels a year shooting XTC with .223 for the last ~15 years. No crimp ever. Never had bullet set-back issues. Never. No crimp needed.

Reproducing the same load is a lot easier if you don't have to worry about crimp and different crimps for slightly different case legnths.

 

[Sniper Uncle]

I like a 55 gr Nosler BT, same brass and more Varget. It is without a doubt a compressed (crunchy) load. I don't crimp and the bullet stays where I set it. I'm using standard (expander ball) sizing die and around 3 thou neck tension.

Thanks, Mtn, I'm not seeing any movement of bulllets either. It takes me quite a bit of effort to move it. I'm not seeing primer flattening any more than a slight bit which seems to happen in setting the primers----just slightly. I'm also using a standard FL expander ball sizing die.
I'm also concerned that if I crimp, I might cause pressure issues, similar to loading against the lands with a high charge. Increased resistance to initial movement should increase the pressure spike. TRUE? or FALSE?
I loaded these rounds after using 26gr loads with good success, to get into an OBT node, so backing off is really not an option for this result.

 

[Sniper Uncle]

I haven't seen any real difference in velocity w/ 55 FMJ's, crimped vs not, so I don't think there would be much pressure increase with a normal (light) crimp. Assuming your Amax is similar to my Nosler BT, you have plenty of room before you’ll have unsafe pressure issues.

I would be hesitant to take a really high quality bullet like the amax that was carefully made, then squeeze it with a crimp.

Never had a compressed charge push the bullet back out any. My only issues have been with improper neck tension; one was commercial reloads that didn’t have correct neck tension and I think it was caused by old work hardened brass and the other was some reloads of mine not too long ago. I still don’t know what I did or didn’t do to cause it, but another run through a sizing die corrected it.

Thanks, Mtn. Are you aware of ever having the bullets pushed back in during cycling of the gun? One of the earlier respondents was concerned that this might happen, causing unsafe pressures. I think with the compressed load that this circumstance would be highly unlikely.

My thought was to go to the range and possibly load a magazine with every first round being some of the 23gr Varget that I have, and every second round with the 26.1's then, shoot a 23gr, let the gun cycle itself, manually pull the next (26.1gr) out, etc, and check all the 26.1's for any bullet movement. This way, the gun is cycling itself to load the heavy ones where we are concerned about deeper seating, but they are not being fired, so I can see any effect of the gun action in this regard.
Thanks for your input,

 

[Sniper Uncle]

Same, all semi-autos get a crimp from the Lee Factory Crimp die. With semi-autos the there is the opportunity for set-back while the round is stripped from the mag by the bolt and placed in the chamber. If this happens you have a kaboom on your hands.

Bolt action or anything single shot gets no crimp.

Point received. I did look again at QuickLoad, and you can go from .312 seating depth (standard) to .365 seating depth before you start to have the pressure issues. That is quite a change, and it seams to me that, with the amount of work it took me to move the seated bullet, a light crimp might not hold against enough force to move it that far. Maybe I'm stupid here, but I don't see it. If you are going to crimp enough to prevent that much movement, aren't you increasing neck tension to the point where you are setting up the same situation you were trying to avoid---too much pressure?

 

[milo 2.0]

Uncle,
You said you bought 2k cass of once fired mil brass, and fired it also. When crimping, if all your brass is not trimmed to the same length, crimping is kind of hit and miss. What die do you crimp with, taper or Lee collett. I'm under the assumption taper crimp is correct, unless you're crimping cannulure bullets, where a roll crimp would work.
I wouldn't us that Lee collett crimp on anything.
I run 748, about the exact same thing as varget, 26gr should be fine, up to 27gr for 50 gr bullets, 25gr for 68 gr bullets.

I don't even try to crimp anymore because of brass length, never seen any problems in anyones gun from not doing it. I have a Giraud annealing machine and am surely not going to anneal .223 brass either, people shot the shit out of this crap before the annealing craze without issue.

 

[gixxer822]

yes i have personally seen it. but tht doesnt mean its a common occurance. this topic has been argued alot and theres no right or wrong way. its personal preference. as long as reloaders, in particular new reloaders are aware of the issues or options from both sides its all good. some guys love to crimp the dog shit outta rds and thts where guys invented tools like the consistant crimp. basically a torque gauge you attach to your press. IMO its useless. id run a batch with a lite crimp and some w/o and see wht your rifle likes

 

[JGorski]

I never use a crimp when I load for my son's RR carbine.

 

[Sniper Uncle]

Uncle,
You said you bought 2k cass of once fired mil brass, and fired it also. When crimping, if all your brass is not trimmed to the same length, crimping is kind of hit and miss. What die do you crimp with, taper or Lee collett. I'm under the assumption taper crimp is correct, unless you're crimping cannulure bullets, where a roll crimp would work.
I wouldn't us that Lee collett crimp on anything.
I run 748, about the exact same thing as varget, 26gr should be fine, up to 27gr for 50 gr bullets, 25gr for 68 gr bullets.
I don't even try to crimp anymore because of brass length, never seen any problems in anyones gun from not doing it. I have a Giraud annealing machine and am surely not going to anneal .223 brass either, people shot the shit out of this crap before the annealing craze without issue.

Milo, yes, I bought 2k once fired. I am on the first loading of said brass. I am trying not to crimp, as I don't think it is necessary. My plan was to fire these all once, making two firings total, and then anneal, trim, etc. That way, the cases are closer to the chamber size of our gun, and I can trim etc. to customize/optimize the brass. I thought to anneal the brass at this time to prevent issues with neck tension due to hardening. Thanks for the input.

" Are you aware of ever having the bullets pushed back in during cycling of the gun? "

Not sure, but probably so. The lot of bad re-loads I bought from a local shop had some serious tension issues on some of the cartridges. The brass they used was worn out pickup from their range. I even had a primer come loose in the mag with these; locked down… On more than one occasion, I removed an unfired cartridge from the chamber to see a bullet set back far enough that a little powder could get past the bullet. No proof, but out of the 500 or so (don’t remember amount) I'm pretty sure I fired more than one cartridge with the bullet set back. My rifle never blew up. This was many years ago and I would not fire them today…

For what it’s worth, I don’t crimp any .223’s w/o a cannilure. No issues that I’m aware of with bullet setback, but I am careful to not chamber the same round over & over from the mag.

Mtn, I understand why those might have moved. I am only using handloads that I made, or military new. I don't think this issue should surface here, Thanks again for your help.

yes i have personally seen it. but tht doesnt mean its a common occurance. this topic has been argued alot and theres no right or wrong way. its personal preference. as long as reloaders, in particular new reloaders are aware of the issues or options from both sides its all good. some guys love to crimp the dog shit outta rds and thts where guys invented tools like the consistant crimp. basically a torque gauge you attach to your press. IMO its useless. id run a batch with a lite crimp and some w/o and see wht your rifle likes

Thanks, gixxer. I am coming to that conclusion myself, and I think that all the posters here have helped me make up my mind. I don't plan to crimp, but I have developed a method to check to see if I see movement---described above in a post--- and my plan right now is continue cautiously and watch results, ready to modify my routine as called for. I do thank everyone for your opinions, and the information given has been gratefully received. I like to get a discussion going, and then pick what I feel is best out of the various methods discussed, and develop my own method. You have all helped tremendously. Please don't feel that my not taking your suggestions means I don't value them. They all play together in my mind to help me develop my own method.

Thanks again, everyone

 

[gixxer822]

update when you get results brother. pix and real world data is wht we all learn from.

 

[Sniper Uncle]

update when you get results brother. pix and real world data is wht we all learn from.

I will be happy to. Her gun is doing quite well with the 26.0 grains, and uncrimped, so pending a test on bullet movement, I plan to move forward. I shall post results, whether positive or negative.

 

[KYpatriot]

Uncle,
You said you bought 2k cass of once fired mil brass, and fired it also. When crimping, if all your brass is not trimmed to the same length, crimping is kind of hit and miss. What die do you crimp with, taper or Lee collett. I'm under the assumption taper crimp is correct, unless you're crimping cannulure bullets, where a roll crimp would work.
I wouldn't us that Lee collett crimp on anything.
I run 748, about the exact same thing as varget, 26gr should be fine, up to 27gr for 50 gr bullets, 25gr for 68 gr bullets.

I don't even try to crimp anymore because of brass length, never seen any problems in anyones gun from not doing it. I have a Giraud annealing machine and am surely not going to anneal .223 brass either, people shot the shit out of this crap before the annealing craze without issue.

Hmmm....I thought the point of the Lee collet crimp was to take case length out of the equation, resulting in a more consistent crimp/tension. Seems superior to taper crimp dies for that reason to me. Am I wrong?

 

[280nosler]

I'll take a slightly different stance. If you are using thick necked brass (read as military 5.56) and using quality dies, and you have measured several from the inside neck before seating, you may not need to crimp. That being said, I crimped my AR rounds for the first 4-5 years before I started reloading 308 with Redding dies, and found out how much better they were than what I was using. After I switched, I tried a few rounds (last round in the mag) and went through 10 mag dumps from a 20 round mag (never firing the last round) and measured before and after, and the change was .0005 (the smallest measurement my caliper goes to). To me that is essentially no set back. I tried the same with a crimped bullet, and surprise, there was zero setback.

I had an old D&H steel mag and dropped it in it's spline (from 6 foot) 12 times with loaded bullets, and of the 10 rounds in the mag, 2 had .0005, 5 had .001, 2 had none, and 1 had .0015 setback. For grins and giggles I tried with my old set of dies, and the setbacks from the mag drop were dangerous - 4 - .002, 1 - .0025, 3 - .003, 1 - .0035, 1 - .0045.

It should be said that the vast majority of bullets I fire are 55 grain Hornady FMJ-BR, with cannelure. I have found the best is to have a slight taper crimp into the cannelure for best results.

 

[EddieNFL]

I've witnessed crimped rounds setback; not enough neck tension. No crimp here...gas or bolt.

 

[Sniper Uncle]

I'll take a slightly different stance. If you are using thick necked brass (read as military 5.56) and using quality dies, and you have measured several from the inside neck before seating, you may not need to crimp. That being said, I crimped my AR rounds for the first 4-5 years before I started reloading 308 with Redding dies, and found out how much better they were than what I was using. After I switched, I tried a few rounds (last round in the mag) and went through 10 mag dumps from a 20 round mag (never firing the last round) and measured before and after, and the change was .0005 (the smallest measurement my caliper goes to). To me that is essentially no set back. I tried the same with a crimped bullet, and surprise, there was zero setback.

I had an old D&H steel mag and dropped it in it's spline (from 6 foot) 12 times with loaded bullets, and of the 10 rounds in the mag, 2 had .0005, 5 had .001, 2 had none, and 1 had .0015 setback. For grins and giggles I tried with my old set of dies, and the setbacks from the mag drop were dangerous - 4 - .002, 1 - .0025, 3 - .003, 1 - .0035, 1 - .0045.

It should be said that the vast majority of bullets I fire are 55 grain Hornady FMJ-BR, with cannelure. I have found the best is to have a slight taper crimp into the cannelure for best results.

Thanks for this info. I think I'll put Redding dies on the wish list. Having said that, I looked at your results on the drop, and I have this to say. QuickLoad says that with the load that I have, a change in seating depth from 0.312 to 0.365 is still not creating pressure issues. 0.366 is where the problem begins. This is a difference of 0.053, which is less than the worst difference you listed. (I think you meant 0.020, 0.025, 0.030, 0.035, and 0.045, which is ten times worse than what you wrote but still 0.008 less than a seating depth listed as fine.)
Did I totally miss something here?
I agree on the good quality brass, I will research dies to get a good set, and I will anneal and trim next firing, after "fire-forming this time to get closer to my gun's chamber.
I appreciate the info,
Thanks

 

[280nosler]

Thanks for this info. I think I'll put Redding dies on the wish list. Having said that, I looked at your results on the drop, and I have this to say. QuickLoad says that with the load that I have, a change in seating depth from 0.312 to 0.365 is still not creating pressure issues. 0.366 is where the problem begins. This is a difference of 0.053, which is less than the worst difference you listed. (I think you meant 0.020, 0.025, 0.030, 0.035, and 0.045, which is ten times worse than what you wrote but still 0.008 less than a seating depth listed as fine.)
Did I totally miss something here?
I agree on the good quality brass, I will research dies to get a good set, and I will anneal and trim next firing, after "fire-forming this time to get closer to my gun's chamber.
I appreciate the info,
Thanks

I read this, and went back through my notes and started to think oh shit. It looks like I may have had missed the decimal in my notes. My 5.56 reloads are trimmed to 1.750 inches, my bullet is the hornady 55 grain FMJ-BT w/c and my load to length is longer then what is listed in the Hornady book - 2.2175. Now I know there is no problem with the slight setback but Hornady calls for 2.200 as the COAL and 2.190 would be bad in terms of a pressure spike. For those out there wondering why I load so long, it is quite simple it is the shortest I can load to have my taper crimp in the cannelure. A load of 2.200 would put the bullet cannelure past the end of the neck, and therefore the taper crimp would not engage the cannelure. My 223/5.56 I consider anything with this bullet shorter than 2.195 as being simply unacceptable.

 

[milo 2.0]

Hmmm....I thought the point of the Lee collet crimp was to take case length out of the equation, resulting in a more consistent crimp/tension. Seems superior to taper crimp dies for that reason to me. Am I wrong?

KY,
I have no idea what the point of their crimp is, never researched it, and probably won't. I've just seen some crimped with a Lee and was amused to say the least.
As for being superior, I'll never shoot it so I can't say.

 

[280nosler]

KY,
I have no idea what the point of their crimp is, never researched it, and probably won't. I've just seen some crimped with a Lee and was amused to say the least.
As for being superior, I'll never shoot it so I can't say.

In my experience you have to be real careful with the lee crimp. I have a friend try some reloads and we ended up pulling the bullets and 8 of 10 ended up being deformed.
This was one of the worst.

 

[LRDD]

I have never crimped a round for gas or bolt ever. Never had an issue.

 

[355sigfan]

I don't crimp my gas gun or my bolt gun rounds and have not had an issue. I used to crimp my gas gun rounds but after reading you don't need to here I stopped and noticed an improvement in accuracy. Also if you did get set back on a rifle round generally you lose pressure because seal around the case and bullet is broke you get a strange report that sounds softer. Had this once in a while strangely enough back when I did crimp with ball rounds. Generally bad brass that was over used.

Pat

 

[bjay]

It depends on my bullet.i never crimp rould for bolt gun and i think i never will.on gas i only grip canelur bullets....althou im with guys above if your using expander built with die you 2-4thousand more than enough i think.unless you using bushing die or seperate expander die.should be tight enough

 

[Ghillie man]

Great thread. New to semi auto reloading what about a small base die?

 

[jwp6114]

Only crimp magnum handgun loads, all rifles neck tension only

 

[1idCat]

Deciding when to crimp is easy:

No Cannelure, No Crimp. EVER.

If the bullet has a cannelure, then you MAY want to crimp, if you're going to fire it in a semi auto. It's usually not needed, but a light crimp doesn't hurt anything.

If you're shooting a magnum revolver, then a heavy crimp is required.



Small base sizing die is not needed on 99.9% of all rifles.

 

[Sniper Uncle]

Deciding when to crimp is easy:

No Cannelure, No Crimp. EVER.

If the bullet has a cannelure, then you MAY want to crimp, if you're going to fire it in a semi auto. It's usually not needed, but a light crimp doesn't hurt anything.

If you're shooting a magnum revolver, then a heavy crimp is required.



Small base sizing die is not needed on 99.9% of all rifles.

Am I correct in believing that I read that a small base die works the brass more than the other ones? If so, this is a good reason to be sure you really need it for your rifle before you got on,as your brass life would really suffer.

 

[rpk762]

I crimp some of my semi rounds. When I do crimp it is just a light crimp. Many service rifle shooters crimp the 77gr SMK. I tried it and my scores also improved. I guy on nodakoutdoors said he measured run out and it was slightly better after a slight crimp. I use a competition seater and did not see a consistent improvement.

If you want to crimp then crimp most of the time it is not needed.

 

[Scooter64]

I loaded dummy rounds in the past using them to function test my magazines. If the magazines were gtg , the heads actually move out of the case increasing cartridge overall length after cycling the dummy rounds many many times. If the mags were messes up and make the round dive and cause failure to feed it would take many fail to feeds for the Heads to go into the case if you had proper neck tension.

what i'm saying in regards to ar's If round feeds with no problems there wont be any problems. If there was a failure to feed i would clear it and disregard the failure to feed round till it was inspected.

 

[Sniper Uncle]

Thanks, Scooter, good to know.
Interesting information on the 77SMK's, rpk, Thanks