Crimping rifle rounds

[brutus51]

Getting ready to reload 6.8SPC, bought a variety of 100 to 120gr. bullets with and without cannelures along with both a roll crimp and taper crimp seating die's. Question is how much crimp do you folks recommend for precision shooting?

 

[Varminterror]

None for precision shooting.

 

[troy fairweather]

yup you don't need any crimp, even with bullets with the cannelure.

 

[brutus51]

Yeah I agree for bolt actions but this is my first semi and I'm concerned about bullet setback.
I was taught to treat lever actions the same as revolvers and apply a roll crimp.

 

[243winxb]

I measured some factory Federal 30-06 fmj that had a taper crimp into a cannelure . The best i could measure was .0015"

Old military test has crimp info & chart.https://apps.dtic.mil/docs/citations/ADA341390

http://www.exteriorballistics.com/reloadbasics/gasgunreload.cfm

I dont crimp. When i had a M16 or 30 wcf, still no crimp. Neck tension is best.

 

[jmorris]

Zero for me. I try to not change the shape of a bullet and if you are crimping brass that has no where to go without distorting the surface of a bullet, I don’t do it.

 

[Galil5.56]

I'd pretty much go with none in this application, esp with really good neck tension. Heavy revolver loads, and tube mags holding multiple rounds to hammer the other bullets with recoil, and spring tension are another kettle of fish.

Now, for my military rifles that really hammer the round on loading (MAS 49/56 w/o feed cuts is BRUTAL) and Argentine 7.62x51, I will crimp... These are not tack driver rounds, and I do give them some crimp. I even crimp for my SVT-40, Galil ARM, and AG-42 out of habit and to match mil-spec ammo. Again, I'm not trying to hit itty bitty bullseye targets... More like minute of rock, can, dirt clod. Good luck.

 

[Lennyjoe]

Throw the dies in the corner and let them collect dust. Better yet, for the 6.8 send them back and get a refund.

 

[Random 8]

I have fired thousands of rounds of 5.56, 7.5 Swiss and 30-06 M1 Garand in matches over the years, as well as a smattering of 6.5Swedish and 7.62x54R. I have never crimped a single round. The only time I have ever seen bullet setback was single loading 5.56 when I misaligned a round and stovepiped it closing the bolt. The only crimped rounds I have fired in competition were M2 Ball or GP11 as issued for specific matches, and it shows on the targets vs unrestricted ammo matches.

IMHO it is not necessary for most rifle ammunition period.

 

[Nature Boy]

Yeah I agree for bolt actions but this is my first semi and I'm concerned about bullet setback.
I was taught to treat lever actions the same as revolvers and apply a roll crimp.

I didn’t crimp for my M1A. With an average amount of neck tension it’s not necessary

 

[cfullgraf]

I'm just like all the other responses, I do not crimp my bottleneck rifle rounds shot in bolt or semi-auto rifles.

For rifles with tubular magazines like most lever action rifles, they generally get crimp due to the bumping the ammunition gets in the tube under recoil.

Also, some folks crimp some of the shoulder buster rounds like 458 Win Mag due to the impressive recoil of the guns

In any case, no need to crimp 6.8 SPC ammunition. Just make sure you have adequate neck tension.

 

[lightman]

I'll be another that says no crimp. The only rifle rounds that I crimp are those shot in rifles with tubular magazines.

 

[243winxb]

The military crimp test is fawed , imo.

The crimp test should have been repeated after correcting the main problems.
Problems- 1. to much free air space in the round.
2.To little bullet shank in the case. (OAL)
3. Powder.

A powder ignition problem would benefit from a crimp.

Note that 2 different primers were tested.

 

[Bfh_auto]

If you have a digital scale, place a dummy round on it and push down on the bullet with a piece of wood. It will surprise you how much pressure it takes to move the bullet.

Digital bathroom scale. Not powder scale.

 

[edwardware]

Digital bathroom scale. Not powder scale.

I was about to say!

If you can do that with your powder scale, you either have low neck tension, or a cannon.