To crimp or not to crimp?


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J23
November 20, 2008, 11:04 PM
Loading up the 77 SMK/24.0/Varget load for the M4. I have a Lee Factory crimp die, but I dont like the way it crimps into the jacket on the SMK which does not have a canneture. Crimp or no crimp?? Experiences?

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ar10
November 21, 2008, 12:00 AM
I don't crimp on my rifles unless the bullet has a cannalure or I'm loading handgun rounds.

Otto
November 21, 2008, 01:12 AM
No crimp. Even if it had a cannelure, I wouldn't crimp.

10 Spot Terminator
November 21, 2008, 02:25 AM
I own Lee factory crimp dies for most of the calibres that I shoot. Having read Richard Lees reloading manual some 15years ago before I even purchased my first reloading setup it was clear to me there were situations where crimping was indeed the way to go . If you use a cannelure as a reference point for crimping in the majority of cases you are ignoring a more determental point to accuracy and that is seating depth of the bullet in relation to the lands . Crimping in any form serves 2 purposes . One is to keep the bullets from shifting due to recoil of the firearm and can create a host of problems . the second is to create a uniform pressure in the cartridge at the point where the bullet actually breaks free of the case referred to as bullet pull. Benchrest shooters understand this principal and its relationship to accuracy all too well . Many of them have their loads and or chambers customized to allow bullets to actually contact the lands in the barrel when the cartridge is chambered and as they load the bullets one at a time do not need to worry about recoil shifting the seating depth of bullets in the magazine . My personal load testing has shown crimping to provide a slight edge in most all of my heavy calibres and a very noteable difference in those where bullet jump is very lengthy due to short magazines and longer chambers such as in many 300 Win Mags or when using Barnes bullets that indeed love long bullet jump to perform properly. In essence I have noted a reduction in flyers when shooting longer shot strings and have to attribute that to more consistant reloads shot to shot . The chronograph as well has shown signifigant redux in extreme spreads as further testimony to the effect crimping has on a given loads performance . The choice is yours of course but I myself rest easier when I am on the hunt for a possible trophy of a lifetime knowing I have done everything possible I can to get that one good shot ,,,, welcome to the never ending learning curve of reloading . 10 SPOT

10 Spot Terminator
November 21, 2008, 02:33 AM
I own Lee factory crimp dies for most of the calibres that I shoot. Having read Richard Lees reloading manual some 15years ago before I even purchased my first reloading setup it was clear to me there were situations where crimping was indeed the way to go . If you use a cannelure as a reference point for crimping in the majority of cases you are ignoring a more determental point to accuracy and that is seating depth of the bullet in relation to the lands . Crimping in any form serves 2 purposes . One is to keep the bullets from shifting due to recoil of the firearm which can create a host of problems . the second is to create a uniform pressure in the cartridge at the point where the bullet actually breaks free of the case referred to as bullet pull. Benchrest shooters understand this principal and its relationship to accuracy all too well . Many of them have their loads and or chambers customized to allow bullets to actually contact the lands in the barrel when the cartridge is chambered and as they load the bullets one at a time do not need to worry about recoil shifting the bullets and at the same time by having the bullets up against the wall as they call it use the chamber to create the bullet pull uniformity verses crimping. My personal load testing has shown crimping to provide a slight edge in most all of my heavy calibres and a very noteable difference in those where bullet jump is very lengthy due to short magazines and longer chambers such as in many 300 Win Mags or when using Barnes bullets that indeed love long bullet jump to perform properly. In essence I have noted a reduction in flyers when shooting longer shot strings and have to attribute that to more consistant reloads shot to shot . The chronograph as well has shown signifigant redux in extreme spreads as further testimony to the effect crimping has on a given loads performance . The choice is yours of course but I myself rest easier when I am on the hunt for a possible trophy of a lifetime knowing I have done everything possible I can to get that one good shot ,,,, welcome to the never ending learning curve of reloading . 10 SPOT

P-32
November 21, 2008, 03:34 AM
I shoot High Power competivley. We go out to 600 yards with iron sights. I have several service rifles I use for matches including those chambered in '06, 308 and 223. My main service rifle is a tuned AR and I shoot a lot of 77 and 80gr. SMK's. But I do enjoy shooting a wood gun once in awhile. The only way I can afford to shoot as much as I do is by reloading.

Another good 77 gr SMK load is with Reloder 15 and Remington 7 1/2 primers. Work up to 24.4 grs. of the Re 15 which burns cleaner than Varget. CCI BR's are worth a try too.

If the Lee FCD was so good, every High Power shooter would be using them. Trust me.

I do crimp things like 30-30, 9mm, 38, 357, 40 and 45ACP. The pistol rounds are taper crimed just enough to remove the bell. The revolver rounds are roll crimped. The amount of roll crimp depends on what powder is used.

ar10
November 21, 2008, 08:35 AM
I shoot High Power competivley. We go out to 600 yards with iron sights. I have several service rifles I use for matches including those chambered in '06, 308 and 223. My main service rifle is a tuned AR and I shoot a lot of 77 and 80gr. SMK's. But I do enjoy shooting a wood gun once in awhile. The only way I can afford to shoot as much as I do is by reloading.

Another good 77 gr SMK load is with Reloder 15 and Remington 7 1/2 primers. Work up to 24.4 grs. of the Re 15 which burns cleaner than Varget. CCI BR's are worth a try too.

If the Lee FCD was so good, every High Power shooter would be using them. Trust me.

I do crimp things like 30-30, 9mm, 38, 357, 40 and 45ACP. The pistol rounds are taper crimed just enough to remove the bell. The revolver rounds are roll crimped. The amount of roll crimp depends on what powder is used.

I just finished reloading 3 different powders for my CZ (7.62x39). The results were interesting, 1680, H322, and RE-7. My best load was 24gr RE-7. At 100 yds using a 125gr .311 SP I hit 5 in the bull key holing. The rest using the same bullet from min to max charges didn't even come close, with the 1680 doing the poorest. I did 90 rounds in 5 round groups, going by the Sierra load manual. The only powder I didn't get was the VV. It was unavailable.

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