Roll or taper crimp .308 Win?

[bottlerocket]

So looking through my catalogs, Hornady offers a 2 die set for the .308 Win which has the size/deprime and the seat/roll crimp. But Dillon offers a 3 die set for .308 Win which has the size/deprime, seat, and then the taper crimp. Is there a certain advantage to using the taper crimp? I am shooting a Savage 111 so I figured a roll crimp would be fine. Does the taper crimp only become necessary if I am reloading 7.62 for an auto?

[chainsaw]

personally,I never crimp for my bolt guns.It's not needed unless you are loading for a very high recoil round or a tube magazine.If you are worried about uneven neck tension,buy a competition type neck size die.

[drybean]

no reason to overwork your brass
drybean

[helotaxi]

Only way to find out if a crimp is necessary is to try some dummy loads and see if there is bullet set-back or creep on chambering. It's a non-issue with a bolt gun and will probably be a non-issue with a semi-auto as well provided that you have adequate neck tension.

[GaCop]

I rarely crimp my AR loads and have no chambering problems but much better accuracy than crimped loads.

[Uncle Jack]

Like most, I seldom crimp rifle loads. I used to crimp all my hunting loads just because I'm a paranoid old poo head.

If you do decide to crimp, roll crimp on bullets with a cannalure and taper crimp flat sided bullets. You'll get less deformation that way.

uj

[Nor Cal Mikie]

I don't even crimp loads for my M1A. No use working the brass more than neded.

[Slim Jim]

For one rifle I have, Rem. 700 HB with an extremely long throat, I use a Lee Factory crimp die to give a moderate crimp due to the bullets being out so far to get close to the rifling. It has zero effect on the accuracy or case life and provides me with a little peace of mind.

Slim

[Warthog]

For one rifle I have, Rem. 700 HB with an extremely long throat, I use a Lee Factory crimp die to give a moderate crimp due to the bullets being out so far to get close to the rifling. It has zero effect on the accuracy or case life and provides me with a little peace of mind.

Slim


I was using the Dillon dies for .308 which came with my Dillon 650 reloader. I had some chambering problems which was traced to a little too much taper crimp. The die pushed down on the end of the brass causing the shoulder to bulge out a little. I replaced the die with the Lee die, which uses a collet. The collet makes contact with the shell holder, and moves up into the die with the brass. The taper in the die squeezes the collet into the brass, so there is no downward pressure. Problem solved! Not all Lee dies use a collet.

I have not done any tests to determine if a crimp helps or hurts. I read is some of the load data books that state that a crimp can help, but I see many here believe it can hurt. Perhaps it depends on the powder. Some types might have to reach a pressure/temperature before the bullet is released to insure complete combustion and reproducibility. Some powders ignite better than others.

[Slim Jim]

From Warthog,

I was using the Dillon dies for .308 which came with my Dillon 650 reloader. I had some chambering problems which was traced to a little too much taper crimp. The die pushed down on the end of the brass causing the shoulder to bulge out a little. I replaced the die with the Lee die, which uses a collet. The collet makes contact with the shell holder, and moves up into the die with the brass. The taper in the die squeezes the collet into the brass, so there is no downward pressure. Problem solved! Not all Lee dies use a collet.

I have not done any tests to determine if a crimp helps or hurts. I read is some of the load data books that state that a crimp can help, but I see many here believe it can hurt. Perhaps it depends on the powder. Some types might have to reach a pressure/temperature before the bullet is released to insure complete combustion and reproducibility. Some powders ignite better than others.


[/quote]

Warthog,
We've never had to go beyond IMR 4064, RL-15, IMR 4895 and most recently Ramshot Tac to find excellent shooting loads out to 500yds. With several different shooters and rifles we've conducted blind chambering tests to see if the crimp helped/hurt the consistency of both 1st shot cold bore and grouping at the same distances. After shooting close to a thousand rounds between us no one found any difference in accuracy out to the same 500 yds. So I only crimp when I feel that the bullet may have to little neck tension or a shallow seating depth and am comfortable that the results will be satisfactory under any condition. By the way, we conducted our tests at 200,300 and 500 yds. Three Remington 700's and 2 Savage 10 FP's were used in the test, all with Factory Heavy barrels. The rifles had as little as 570 rds to a max of 3750 rds fired thru them. Each rifle was tested with it's own accuracy load.

Slim

[Warthog]

From Warthog,

I was using the Dillon dies for .308 which came with my Dillon 650 reloader. I had some chambering problems which was traced to a little too much taper crimp. The die pushed down on the end of the brass causing the shoulder to bulge out a little. I replaced the die with the Lee die, which uses a collet. The collet makes contact with the shell holder, and moves up into the die with the brass. The taper in the die squeezes the collet into the brass, so there is no downward pressure. Problem solved! Not all Lee dies use a collet.

I have not done any tests to determine if a crimp helps or hurts. I read is some of the load data books that state that a crimp can help, but I see many here believe it can hurt. Perhaps it depends on the powder. Some types might have to reach a pressure/temperature before the bullet is released to insure complete combustion and reproducibility. Some powders ignite better than others.




Warthog,
We've never had to go beyond IMR 4064, RL-15, IMR 4895 and most recently Ramshot Tac to find excellent shooting loads out to 500yds. With several different shooters and rifles we've conducted blind chambering tests to see if the crimp helped/hurt the consistency of both 1st shot cold bore and grouping at the same distances. After shooting close to a thousand rounds between us no one found any difference in accuracy out to the same 500 yds. So I only crimp when I feel that the bullet may have to little neck tension or a shallow seating depth and am comfortable that the results will be satisfactory under any condition. By the way, we conducted our tests at 200,300 and 500 yds. Three Remington 700's and 2 Savage 10 FP's were used in the test, all with Factory Heavy barrels. The rifles had as little as 570 rds to a max of 3750 rds fired thru them. Each rifle was tested with it's own accuracy load.

Slim
[/quote]



Slim
Thank you for that information. It is really helpful when there is a test performed. The challenge in this sport is that there are so many variables in accuracy it is hard to determine if something you did helped or something else changed. It's like trying to solve an equation with too many variables. Thank you again for sharing the data. And thanks to all the other people who responded. I really like this site. I've seen others which were not so helpful and sometimes very rude. Maybe Savage shooters are nicer people?

[jonbearman]

I always taper crimp in my gas guns but the bolt guns are ok with good neck tension,at least .002 thou neck tension.Get a bushing type die and full length and mic a loaded cartridge and select a bushing .003 less than your loaded round.This will give you .002 when you are finished because you lose a thou with brass springback. If you want real consistent neck tension then anneal the cases every 4th or 5th reloading and this alone will extend the brass life alot.I have some chinese .223 brass on its 35th loading and wish I had more of that norinco brass.It is better than lake city which is my favorite.Back to the .308.I would trim to a standard length and just skim trun the necks to make sure the wall thickness is all similar.Do this if you want to wring out the accuracy and weigh your cases into groups not exceeding 2 grains difference between them.Then load and determine which weight of brass it likes.The lighter the case the larger the volume the case can handle.