To Crimp, or Not To Crimp?

[highnoon]

I want to start reloading 338 Win Mag for my Hawkeye Mark II, but I can't find a definitive answer to this question. Can anyone shed light on whether it's necessary/desirable to crimp these rounds. I will be using 225 and 250 grain bullets.

I have a box of Barns cartridges that is crimped, and three boxes of Hornady that is not crimped. Both are 225 grain.

Thanks.

[Scharfschuetze]

I think that if you are loading anywhere near maximum for your 338 (say over 2,100 fps with your 250 grain slugs), a crimp to hold the boolit in place under recoil might be beneficial. It can prevent your boolit from getting pushed deeper into the case from the face of the magazine during recoil.

If you are just loading plinking rounds at lower velocities, then probably not.

Try your loads both ways. A crimp may help out with your ballistic uniformity, but you'd need to test that over a chronograph or for vertical dispersion or at long range to really tell. A crimp might also help with group sizes, but again, only your rifle and loads and testing will tell you that. Anything else is just speculation.

Jacketed bullets can take a lot more neck tension than cast boolits, and thus (probably) the difference in crimps between the Hornady and the Barnes factory fodder.

[gwpercle]

The proper answer is, load some up crimped and some others un - crimped, test them at the range for accuracy and boolit movement.
That's what handloading is all about , tailoring your ammo to your rifle.
There is really is no yes or no answer. Some boolits will react better crimped and others will shoot better not crimped. Also depends on the powder used...I wish I had an easy answer but if it was easy......it wouldn't be so much fun .
Gary

[lobogunleather]

A crimp would be unnecessary for ammunition used in a single shot rifle, although the crimp might be advantageous in achieving the best ignition and combustion in some cartridges. Some of the slower burning powders benefit from a moderate to heavy crimp to assure best ballistic performance.

For ammo having significant recoil intended for use in a repeating rifle crimping will reduce or eliminate any tendency of the ammo in the magazine to suffer from backing out of the seated bullets under recoil, which can interfere with proper functioning of the rifle.

Ammunition for rifles with tubular magazines can benefit from crimping to prevent bullets from being driven more deeply into the cases under recoil, as well as preventing the bullets from backing out.

So, several issues can be in play.

[highnoon]

Thanks all for the info. Looks like I'll just have to experiment and see what works best. Like "gtwpercle" said......if it were easy, then it wouldn't be so much fun.

Thanks again.

[clum553946]

What lobogunleather said.

[flint45]

Test and shoot and have fun doing it that will tell you what is best for your rifle.