The effects of crimping precision reloads in a semi auto rifle

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[ARCHIVED THREAD] - The effects of crimping precision reloads in a semi auto rifle

Posted: 7/16/2010 7:04:23 PM EDT

I have had my Lothar Walthar barreled upper receiver in 5.56 for 3 months now, and finally today have i been able to produce some groups that i can actually show off.

The difference? A very light crimp using the Lee crimp, and seating bullets shorter then the manuals say. Most people say to seat to magazine level but seating shorter helped, but crimping got rid of one problem i have been having for awhile....I would always have 4 shots really close, but a fifth shot being what seems like a mile away.

First off is PPU bullets i havent been able to get good groups with, the crimped rounds seemed to have improved a little

Next is 55gr V-max, (both are 24.0gr, i wrote 25. by accident)

as you can see the mile away flier seems to be gone.

Ok here is an example of no crimp, the group could have been good but again for some reason one round is a mile off. The group on the right was screwed up after the second shot so i continued to shoot quickly and not take my time.

I had only 8 rounds of this(ran out of brass), So I crimped five which are on the left, uncrimped is of course the right three shot group Also the right group was rushed and shot quickly.

Alright here is what a lightly crimped reload can do. Again, the right group was fired at a fast pace, about 1 round every 1-2 seconds, where the one of the left was anywhere from 5-10 seconds between shots

Posted: 7/16/2010 8:36:58 PM EDT

[#1]

Fixed Em For Ya courtesy of On Target

Posted: 7/16/2010 10:07:48 PM EDT

[#2]

I'm digging that software.

Posted: 7/17/2010 5:50:12 AM EDT

[#3]

Good work. It does appear to improve the vertical. Them PPU's ain't all that bad after all. Try the 75's yet, they work better for me.

Posted: 7/17/2010 9:46:39 AM EDT

[#4]

Quoted:
Good work. It does appear to improve the vertical. Them PPU's ain't all that bad after all. Try the 75's yet, they work better for me.

Im going to try swapping the PPU 75 in for the hornady load that got .66moa. Between then UBR stock and the crimping the PPR projectiles are showing they can do 1moa.

Posted: 7/17/2010 10:42:15 AM EDT

[#5]

I have been shooting 77 grain Nosler Custom Competition loaded with 22.5 grain Varget/LC brass/CCI400 and it has been my experience that the rounds with the light crimp are more accurate shooting from the bench. I am also more comfortable using the rounds crimped this way since the Military Shoot that I compete in requires me to load single rounds in both the prone and standing events, the crimp makes it less likely that the bullet will shift in this type of loading.

Posted: 7/17/2010 3:04:53 PM EDT

[#6]

Seems your examples show the effects of the shooter not the crimping.

Posted: 7/17/2010 3:09:40 PM EDT

[#7]

What is the rifling rate and pattern of your rifle? I have an LW barrel with standard match rifling (not poly) in a 1:8 twist and it shoots the 75gr BTHP Match (hornady) bullets like lazer beams. I haven't tried the lighter bullets that you are using, but I would suggest that you try some different projectiles yet too. As far as crimping goes, I don't crimp my match bullets; however, it may be that the crip is producing a more uniform neck tension for you (giving you more constant velocity and less vertical stringing). You probably said this, but what type of brass are you using?

Posted: 7/17/2010 5:58:40 PM EDT

[#8]

Its a LW 1:8 barrel

I just recheckek all my data, and i had a few things wrong in my post, as i was in a rush to post it.

Quoted:
Seems your examples show the effects of the shooter not the crimping.

The targets that I know whre my fault i pointed out, as i didnt have time to crop them out. I used a bipod and a rolled up towl under my UBR, with this the crosshairs didnt move one bit. While there will always be human error I am not the first person to have similar results with crimping.

Posted: 7/18/2010 1:48:33 AM EDT

[#9]

I loaded 100rds of 23.8gr TAC behind 75gr Hornady bullets, half with no crimp and the other half with a pretty good crimp from a Lee crimp die. In three different rifles, the crimped load shot better than the ones without a crimp (all though none on that particular day were too impressive).

Posted: 8/1/2010 8:21:44 PM EDT

[#10]

InfiniteGrim, I tried out your theory today, (lightly crimping with Lee FCD) some non-Canelure bullets, (the Privi 75's)
And yes indeed, it did help with the vertical dispersion. We may be on to something.

Posted: 8/1/2010 8:30:25 PM EDT

[#11]

If you think of it how much effort must be put into reloading precision reloads to get sub moa groups, it all goes down the toilet when the BCG violently pushes the round out of the magazine, up and against the feed ramps and chamber.

This has to throw the seating depth of the rounds off. The light crimp minimizes the amount the bullet can be setback while the round is being chambered.

Unfortunetly the only times I get to go to the range are with my family therefore I dont have the time to do indepth experiments, and as you can see this is basically thrown together using some of my results from a random range trip. Hopefully I will get back out to the range this weekend. I can also try out the rest of the Prvi projectiles you graciously gave me, this time over varget.

Posted: 8/2/2010 5:35:00 AM EDT

[#12]

I'm glad you got the same results that I did by shortening up the COL of those rounds. As you might remember, I also saw a (slight) increase in accuracy with a light crimp using the 75gr Hornady's. I was using Varget for those loads where I finally got good results, but I tried some TAC loads yesterday with the shorter (2.235") COL and got much better results than I did using TAC and the "standard" COL. Still tweaking the powder charge, but I think somewhere between 22.3 and 23.3 might get me right around MOA.

Posted: 8/2/2010 7:01:53 AM EDT

[#13]

Does anyone remember an article here by Speer about crimping that said in none of their tests did they ever see bullets set back from feeding but their tests did show bullets shoved forward in ar's when the bolt cycles the round if not crimped. It does make sense as it is the same effect as a kinetic bullet puller. Personally I don't crimp, as I just couldn't see an accuracy improvement on my rounds. Looks like this difference of opinion will continue to have adherents to both views which means you have to do what you have confidence in.

I do think the results for the OP would be more valid if he could have someone else load the rounds so that he didn't know whether he was shooting crimped or uncrimped.

Posted: 8/2/2010 2:17:04 PM EDT

[#14]

I'd like to add one of my observations to the conversation please FWIW.

I was having concentricity issues (well still do, just not as bad) and I was checking all of the rounds that I had loaded on my Sinclair fixture and then seperated them by amount of runout. About that point in time there was (and still is) debate as wether to crimp, or not to crimp. So, long story short I took some of the rounds that I had loaded, checked and seperated by runout and ran them through my taper crimp die.

Then I got the idea to recheck them on the concentricity fixture once more for some odd reason and guess what? All of the runout was decreased almost in half of what it was before crimping.

I've been crimping ever since. Personally, I think crimping is a good thing YMMV.

This is sure to shock some folks, but I even apply cannelures to bullets that don't have them and crimp them too. It helps me minimize run-out and have peace of mind about setback. I have never in 34 years of handloading had bullet setback. I wonder if that's what's contributing to better groups when some of you find that crimping does help accuracy because you may also be lowering runout at the same time and not be aware of it. Check them for yourself.

I mostly use this process for ammo for my 2 - AR's with good barrels and glass.

Later,

Danny

Posted: 8/2/2010 3:19:12 PM EDT

[#15]

Quoted:
I'm glad you got the same results that I did by shortening up the COL of those rounds. As you might remember, I also saw a (slight) increase in accuracy with a light crimp using the 75gr Hornady's. I was using Varget for those loads where I finally got good results, but I tried some TAC loads yesterday with the shorter (2.235") COL and got much better results than I did using TAC and the "standard" COL. Still tweaking the powder charge, but I think somewhere between 22.3 and 23.3 might get me right around MOA.

Heh, I've been trying to get sub-MOA groups out of 69gr SMKs over 26gr of Varget. I seem to be hitting "the wall" around 1.36" groups at 100 yards. Of course, this is from a 12.5" bbl (albeit Noveske) in a rifle with a stock trigger, 12x scope, and a loose nut behind the stock

I think I'll try dialing back the charge to 24gr or so and seating deeper. Maybe I can start producing 1" groups from the bench.

eta: A light crimp (.002 difference between case neck and crimped area) generally improves groups slightly in my experience. Never had it open them up.

Posted: 8/2/2010 3:22:40 PM EDT

[#16]

...the crimped rounds seemed to have improved a little...

This is a tough crowd to drop that bomb on. You'll be lucky to escape with your shirt on.

Posted: 8/2/2010 4:58:35 PM EDT

[#17]

I don't know, seem like there are quite a few "crimpers" out there

Posted: 8/2/2010 5:13:32 PM EDT

[#18]

Quoted:
I'd like to add one of my observations to the conversation please FWIW.

I was having concentricity issues (well still do, just not as bad) and I was checking all of the rounds that I had loaded on my Sinclair fixture and then seperated them by amount of runout. About that point in time there was (and still is) debate as wether to crimp, or not to crimp. So, long story short I took some of the rounds that I had loaded, checked and seperated by runout and ran them through my taper crimp die.

Then I got the idea to recheck them on the concentricity fixture once more for some odd reason and guess what? All of the runout was decreased almost in half of what it was before crimping.

I've been crimping ever since. Personally, I think crimping is a good thing YMMV.

This is sure to shock some folks, but I even apply cannelures to bullets that don't have them and crimp them too. It helps me minimize run-out and have peace of mind about setback. I have never in 34 years of handloading had bullet setback. I wonder if that's what's contributing to better groups when some of you find that crimping does help accuracy because you may also be lowering runout at the same time and not be aware of it. Check them for yourself.

I mostly use this process for ammo for my 2 - AR's with good barrels and glass.

Later,

Danny

I had the same observation of the concentricity being tweaked to the good using a light FCD crimp. I was basically called a liar when I mentioned it here lol.

Posted: 8/2/2010 5:23:17 PM EDT

[#19]

Quoted:

Quoted:
I'd like to add one of my observations to the conversation please FWIW.

I was having concentricity issues (well still do, just not as bad) and I was checking all of the rounds that I had loaded on my Sinclair fixture and then seperated them by amount of runout. About that point in time there was (and still is) debate as wether to crimp, or not to crimp. So, long story short I took some of the rounds that I had loaded, checked and seperated by runout and ran them through my taper crimp die.

Then I got the idea to recheck them on the concentricity fixture once more for some odd reason and guess what? All of the runout was decreased almost in half of what it was before crimping.

I've been crimping ever since. Personally, I think crimping is a good thing YMMV.

This is sure to shock some folks, but I even apply cannelures to bullets that don't have them and crimp them too. It helps me minimize run-out and have peace of mind about setback. I have never in 34 years of handloading had bullet setback. I wonder if that's what's contributing to better groups when some of you find that crimping does help accuracy because you may also be lowering runout at the same time and not be aware of it. Check them for yourself.

I mostly use this process for ammo for my 2 - AR's with good barrels and glass.

Later,

Danny

I had the same observation of the concentricity being tweaked to the good using a light FCD crimp. I was basically called a liar when I mentioned it here lol.

Well, there's reloaders and there's handloaders too.

Danny

Posted: 8/5/2010 3:46:49 PM EDT

[#20]

Quoted:
If you think of it how much effort must be put into reloading precision reloads to get sub moa groups, it all goes down the toilet when the BCG violently pushes the round out of the magazine, up and against the feed ramps and chamber.

This has to throw the seating depth of the rounds off. The light crimp minimizes the amount the bullet can be setback while the round is being chambered.

So you're speculating, but wouldn't this be easy to test? Load some rounds minus powder and primer, load into a mag, and drop bolt on an empty chamber. This probably doesn't simulate the actual force of the BCG in live fire, but it's got to be close. Could also remove the trigger to eliminate drag on the BCG (ie, enhance speed) for the test. Measure the OAL before and after this process, or several iterations of it, and see how it changes, if at all.

Posted: 8/5/2010 5:34:48 PM EDT

[#21]

Quoted:

Quoted:
If you think of it how much effort must be put into reloading precision reloads to get sub moa groups, it all goes down the toilet when the BCG violently pushes the round out of the magazine, up and against the feed ramps and chamber.

This has to throw the seating depth of the rounds off. The light crimp minimizes the amount the bullet can be setback while the round is being chambered.

So you're speculating, but wouldn't this be easy to test? Load some rounds minus powder and primer, load into a mag, and drop bolt on an empty chamber. This probably doesn't simulate the actual force of the BCG in live fire, but it's got to be close. Could also remove the trigger to eliminate drag on the BCG (ie, enhance speed) for the test. Measure the OAL before and after this process, or several iterations of it, and see how it changes, if at all.

It would be easy to test, but you would be assuming nothing happens during extraction. Unless you remove extractor from the BCG and carefully pull the round out manually.

Posted: 8/5/2010 6:04:53 PM EDT

[#22]

Quoted:

Quoted:
If you think of it how much effort must be put into reloading precision reloads to get sub moa groups, it all goes down the toilet when the BCG violently pushes the round out of the magazine, up and against the feed ramps and chamber.

This has to throw the seating depth of the rounds off. The light crimp minimizes the amount the bullet can be setback while the round is being chambered.

So you're speculating, but wouldn't this be easy to test? Load some rounds minus powder and primer, load into a mag, and drop bolt on an empty chamber. This probably doesn't simulate the actual force of the BCG in live fire, but it's got to be close. Could also remove the trigger to eliminate drag on the BCG (ie, enhance speed) for the test. Measure the OAL before and after this process, or several iterations of it, and see how it changes, if at all.

It would be easy to test, but you would be assuming nothing happens during extraction. Unless you remove extractor from the BCG and carefully pull the round out manually.

Ya, I assumed that controlled extraction would be part of the test. Thanks for mentioning...

Posted: 8/5/2010 7:35:22 PM EDT

[#23]

I do my crimping to reduce the possibility of setback but I LOVE the case that the Lee FCD came it.

That case alone just screams 'quality' and has got to be making my rounds more accurate.

Posted: 8/5/2010 8:50:31 PM EDT

[#24]

Quoted:
I do my crimping to reduce the possibility of setback but I LOVE the case that the Lee FCD came it.

That case alone just screams 'quality' and has got to be making my rounds more accurate.

I love that lee minimizes cost by not spending a ton on packaging.

I use Lee FCD on my AR loads with about .002 as mentioned above. I find it improves my accuracy.

Posted: 8/6/2010 4:38:09 AM EDT

[#25]

While I'm not at that level of accuracy (1MOA is good for me) I've found the same thing about crimping. My chrono tells me that I get a slightly lower SD with a light crimp on my loads, be they .223 or .357mag, 40s&w, 45acp, 10mm, or even 30 carbine. I also found out recently that a higher load density also gives much more consistent velocities and tighter groups so I've been reviewing my loads with an eye towards reducing the OALs a bit to increase the load density.

Posted: 8/6/2010 5:33:15 AM EDT

[#26]

Quoted:

...the crimped rounds seemed to have improved a little...

This is a tough crowd to drop that bomb on. You'll be lucky to escape with your shirt on.

Boy ,your not kidding there,My best way is to show them, All the guys I shoot around have said" semi autos are not accurate" thats when I wax their ass with my Ar.

Crimping I believe has helped tremendously

Posted: 8/6/2010 10:08:58 AM EDT

[#27]

I have the Lee 223 die set.

how are you guys setting a .002 crimp?

Posted: 8/6/2010 4:08:30 PM EDT

[#28]

One suggestion, try 10 shot groups, that's what the military uses for accuracy testing and it's much more reliable than 5 which many think is the very minumum you should use.

Posted: 8/6/2010 8:22:21 PM EDT

[#29]

Quoted:

Heh, I've been trying to get sub-MOA groups out of 69gr SMKs over 26gr of Varget. I seem to be hitting "the wall" around 1.36" groups at 100 yards.

The 10-shot group pictured below was fired from a semiautomatic AR-15 using 69 grain Sierra MatchKings. You're not going to get groups like this by crimping.

Here's some data comparing a non-crimped load (yellow) to an othewise identical crimped load (green) using the Nosler 77 grain OTM bullet fired from a semiautomatic AR-15 based on three 10-shot groups fired in a row from 100 yards.

Posted: 8/7/2010 6:33:30 AM EDT

[#30]

When I started loading .223 my RCBS seating die was marring the bullet tips, and bending some cases where the bullet got off axis in the seating die (flat base bullets weren't helping either).
I ordered a set of Hornady new Dimension dies with a floating sleeve and better seating stem. So I pulled the stem out of the RCBS die and moved it to the #4 position on my RL 550 tool head and have it set for a light crimp (it will pass the 14 lb test).
I had a piece of Rem 7mm rm brass let go on me doing a work up with RL 22 and a 170-175 gr bullet
with a M 70 Classic (Mauser claw style extractor) and it felt like somebody hit he rifle with a bat.
I had 1 .223 have a small set back before I started crimping, the crimp gives me piece of mind that I wont have anymore setbacks, I really don't want to have a round let go with an Aluminum Rifle against my face, and unless you over crimp and start creating a false cannelure on the bullet, it should help provide consistent tension with the ride from the mag to the chamber.

Posted: 8/7/2010 11:57:04 AM EDT

[#31]

I tried some loads using a light crimp and using 23.5 gr Varget, 75BTHP and 68gr BTHP Hornady bullets. I tried several different seating depths from 2.260/2.255/2.250/2.245/2.240/2.235. with or without crimp, I got same exact results with ALL loads.. 1-1/4"-1-1/2" MOA, VERY consistent... This is through a Superior Barrels 18" SPR.. It shot the 40gr V-max into .75" real consistently. Ive given up on hornady match bullets for it and Im moving to the 77gr and 69gr Sierra MK'S.

Posted: 8/7/2010 8:38:02 PM EDT

[#32]

Quoted:
I tried some loads using a light crimp and using 23.5 gr Varget, 75BTHP and 68gr BTHP Hornady bullets. I tried several different seating depths from 2.260/2.255/2.250/2.245/2.240/2.235. with or without crimp, I got same exact results with ALL loads.. 1-1/4"-1-1/2" MOA, VERY consistent... This is through a Superior Barrels 18" SPR.. It shot the 40gr V-max into .75" real consistently. Ive given up on hornady match bullets for it and Im moving to the 77gr and 69gr Sierra MK'S.

You've got to play with the powder charge. My scale may say 23.5grains, but it could be 24.0grains on your scale.

Posted: 8/8/2010 11:31:03 AM EDT

[#33]

Quoted:

Quoted:
I tried some loads using a light crimp and using 23.5 gr Varget, 75BTHP and 68gr BTHP Hornady bullets. I tried several different seating depths from 2.260/2.255/2.250/2.245/2.240/2.235. with or without crimp, I got same exact results with ALL loads.. 1-1/4"-1-1/2" MOA, VERY consistent... This is through a Superior Barrels 18" SPR.. It shot the 40gr V-max into .75" real consistently. Ive given up on hornady match bullets for it and Im moving to the 77gr and 69gr Sierra MK'S.

You've got to play with the powder charge. My scale may say 23.5grains, but it could be 24.0grains on your scale.

Oh yeah I didnt mention that I did start from min to max on charge also. 23.5 gave a very consistent 1-1/4/-1/2". I would get three or four 7/5" shots going and then 2 or 3 out of five would be out.. Every time, I shot and played with the loads with about 140 of the 75gr and 120 or so of the 68gr.. So I came to the conclusion that they are 1-1/2" moa bullets out of that gun.. Still not too bad. but not great either..

Posted: 8/8/2010 12:47:51 PM EDT

[#34]

What did you do to ensure that the only remaining variables affecting precision were the effect of the crimp, weather, and shooter's ability?

Posted: 8/8/2010 4:54:51 PM EDT

[#35]

Quoted:
What did you do to ensure that the only remaining variables affecting precision were the effect of the crimp, weather, and shooter's ability?

I loaded multiple non crimp loads of the same charges/seating depths and shot side by side groups. Weather was nice and calm on the 3 different days that i tested. I have a very nice/clean RRA 2-stage trigger that breaks clean. I sandbagged the rifle really well front and back. I shot off a bipod and sandbags in the back and back and forth with all those loads. Ive been shooting @ 100 yards off a bench with multiple AR's with different barrels/precision bolt actions(GAP) for about 5-6 years now and I deffinatly know when and what the groups are representing..Mostly because the range I go to is right down the street.. No Im absolutely not the best shooter in the world but my errors are fliers that are usually 1/2" out, or so not 1-1/2".. Im ok with the horn's shooting @ 1-1/2" I will not be very happy if the Sierra's shoot that..

Posted: 8/8/2010 8:28:40 PM EDT

[#36]

I can't post pics here anymore for some reason (photobucket problems) but I worked up some loads ( 5, 10 round loads) with Nosler 77 CC's,TAC,Winchester brass and S&B primers, my best 2 groups (also the hottest,but not at max) had 6 of 10 in one ragged hole,with 4 outside. If I would have stopped at 5 shots, they both would have been smaller than a penny at 100 yards.Light Lee Factory Crimp.Edit to add, the point IMO, it ain't my ammo, it's either Me or the Barrel, when my Kreiger gets here hopefully that will change.BTW I am shooting what a very wise man on AR15's calls "the best $200 barrel you can buy,if that's what you want"

Posted: 8/23/2010 8:40:29 PM EDT

[#37]

Quoted:
I can't post pics here anymore for some reason (photobucket problems) but I worked up some loads ( 5, 10 round loads) with Nosler 77 CC's,TAC,Winchester brass and S&B primers, my best 2 groups (also the hottest,but not at max) had 6 of 10 in one ragged hole,with 4 outside. If I would have stopped at 5 shots, they both would have been smaller than a penny at 100 yards.Light Lee Factory Crimp.Edit to add, the point IMO, it ain't my ammo, it's either Me or the Barrel, when my Kreiger gets here hopefully that will change.BTW I am shooting what a very wise man on AR15's calls "the best $200 barrel you can buy,if that's what you want"

It was the barrel

Sure, it shot O.K., but this new one.... Damn !
From the Tech Support section I posted over 24 hours ago with no replies
Something must have changed since the last time I used Photobucket. Now when I hover your mouse over the image it don't bring up the menu it used to.I can right click to see some options but when I try to post a pic and click preview, the pic is tiny, now what ?
Help me out

[ARCHIVED THREAD] - The effects of crimping precision reloads in a semi auto rifle

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