crimping

[baltz526]

as a debate rages on another site :lol: on the benifits of crimping hunting reloads, i'll bring it up here. here is the problem, you have a long throted weatherby rifle chambered for non weatherby cartrage, 338 win mag, 300 win mag. these guns are certified to shoot a certin group with factory ammo with a crimp and oal standard to factory ammo. since the magazine or bullet, will not allow the bullet to be set near the lands and it is not using match grade chamber or cases. my solution is to crimp at standard oal with bullets with canalure. to gain consistant neck tension, consistant ignition, consistant bullet jump to lands and safer hunting reloads. reloads with no crimp, all other things being equal- might give a 5 shot group with three shots inside 2" 2 flyers spreading group out to 4". with a crimp into canalure groups are under 2". in my 300 win mag this is better accuracy, still not good enough to depend on it for hunting the desert. but better. now my suggestion to the owner of the 338 win mag is to try a bullet with canalure and crimp, but most the reloaders are against this idea, of the opinion crimping will not help, makes no difference in accuracy. to me consistancy equals accuracy, anyway i can gain consistancy helps the overall accuracy of hunting loads.

 

[rick smith]

I only crimp revolver loads and tubular magazine loads. See absolutely no benefit to crimping my hunting loads. My last three shot group from my uncrimped 300WM measured 0.2". Don't think crimping will help that.
You don't have to be at or near the lands to get accuracy. A friend just finished a project with a factory HOWA 223 that shoots absolute bug holes and he is 69thou off the lands. Many of the short action rounds have to be loaded to fit the mag box and not the lands.
I think if you fire enough ammo over a chronograph both crimped and uncrimped you will find all the things you say may not be quite up to the advertisements for those crimping dies.Rick.

 

[baltz526]

so you think that the factory ammo is only crimped to stop bullet migration and my rifle will shoot under 4" groups all day with uncrimped ammo is good :shock:

 

[baltz526]

going through my cronograph sheets, it appears that crimped loads are about 30% more consistant in standard deviation no extreme highs or extream lows. uncrimped run from a high of 59s/d to 6s/d. crimped run 31s/d to 18s/d. not very scientific but might be one reason factory ammo gets crimped. on 10 shot strings thru the cronograph i do not get the random high or low as often with crimps

 

[buckfever]

the only other reason I crimp is some time's heavy recoil will some time's push the bullets back into the case when using 250 gr pills in my 338 win mag other then that I see no reason to do so.

 

[rick smith]

baltz526, if your rifle prefers crimped ammo then feed it crimped ammo. I have seen stanger than that work with different rifles. Your chronograph data doesn't follow mine nor any others I have seen but if it works for you then be happy, you beat the odds. Ought to buy some raffle tickets. Have to wonder if this crimping is so good why the benchrest crowd hasn't jumped on board. There are loaders on all the various boards that like to crimp their ammo and that is fine but crimping is not the final answer to consistant loads. I frequently get single digit SD and most all my loads are under 20 so not crimping is very consistant for me and a lot of other loaders. I went the crimping route many years ago and don't need to visit there again.Rick.

 

[Guest]

You should only be useing three shot groups to judge accuracy of a small diameter barrel hunting rifle! Especially the hotter burning magnum's. Accuraccy should be judged on a cold barrel! So three shots wit at least a minute in between shots. And at least 10 minutes ( depending how warm it is outside ) between groups! And though i can't load my .308 to the lands ( about .125" from the lands ) it's still holding .5" groups at 100 yards. 2.0" at 300. The reason i can't load to the lands is the magazine is too short. But still very accurate!

 

[baltz526]

when doing testing on a load, over the cronograph i'll shoot several shots, as many as ten on my best loads. this can make a pretty good group test. and give very accurate bullet drop info. when sighting in a rifle, 3 shot groups are normal. here is the motive for the post. if you have a rifle that shoots factory crimed ammo into 1" groups and you can not get any reload to shoot under 2", crimping may help. or just buy the $48.00 per box factory ammo, that shoots 1" groups. $600 rebarreling will also fix it, but trimming cases and setting a die is a lot cheaper, or buying a lee crimp die. it would be very interesting to hear a factory ballistic tech explain all the reasons for crimps

 

[Desert Fox]

If your reloads doesn't shoot, crimping won't cure your problem. I have rifle chambered from 338 Win mag to 223 Remington; none of the round are being crimped and no problem with accuracy either.

 

[baltz526]

sorry i'm looking for facts, not suppositions. just because you do not crimp, it dosn't mean crimping might not help with some rifles accuracy. list all the reasons factory ammo is crimped, or all the benifits of crimping realized from factory crimps. you can also give a percentage of benifit for each reason :lol: i understand research and facts have no place in reloading rifle ammo :twisted: but my questions are really very basic. i'm not interested in match ammo or attempting to get match type accuracy, i'm a hunter and attempt to make the best hunting ammo. the factory ammo that is crimped is the best hunting ammo the factory makers can assemble. real data would be nice

 

[rick smith]

The facts I can give you come from years of loading experience and calibers ranging from 22Hornet to 375H&H. I worked up loads for two different 375H&Hs for friends going to Africa. Used 300gr Nosler Partitions and Swift A-Frames. Both rifles shot better groups and had better SDs without crimps. The Noslers gave better penetration but deeper than wanted. The PH told them he didn't want pass throughs. So we went to the A-Frame. It had to be crimped to prevent movement under recoil, the Partition had not moved under recoil.

Worked with several BLRs, 308(3), 358(2), 7/08 and 257Roberts. Tried crimps on all of them. All now shoot uncrimped ammo.

I load for a competitive rifle shooter, military type, M1A1, Springfield, M1 Garrand. No crimps on any. Were you aware that the Match Ammo, military issue, used by the rifle teams is not crimped?

If you like crimping and it works for you then continue to use same but you must realize that there are a lot of loaders who have tried crimping and choose not to use same for various reasons.Rick.

 

[baltz526]

to me, the only reason not to crimp is case life. i do not crimp most the loads i shoot, it is un needed for most cases. but there are some loads that always get crimped. particular bullets in long throated chambers, for example 300 win mag using 180gr accubonds with canalure. 6.5x55 120gr ballistic tip. 300 savage, 150gr Partition. 223 with 55gr fbsp. consistant chamber pressures might be a better reason in some of the older rifles.