To crimp or not to crimp, that is the question (7.62x39)

[Geilt]

So now I've decided to add 7.62x39 to my reloading fetish. Before I start working it I was wondering who here is already reloading it and if you crimp the seated bullet. So far I've received answers ranging from never crimp, always crimp and it depends on the type of bullet you're loading. Personally the last of three answers makes the most logical sense to me but what do I know from a real world expierence.

I'll be shooting from a Yugo SKS if that makes any difference.

Oh, as a follow-up question, what powders work well for this little monster of a cartridge?

[robocop10mm]

I reload 7.62X39 and have since before data was available. I ALWAYS crimp ammo for self loaders. Just remember, case length is critical. Having uniform case length insures uniform crimps. Crimping some bullets (non cannelured) can cause accuracy problems but I only use cannelured bullets in this cartridge. Winchester 123 gr SP's work well in my Chinese SKS.

[rep30cal]

While I have never loaded 7.62x39, I have had .223 rounds that I could
move the bullets with my fingers. I bought a Lee Factory Crimp Die and
it has worked great. The newer die can only pinch so far and it bottoms
out so you can't over crimp, it is an extra step that some feel is not
needed but I feel better safe than sorry. I use it in .308 and .223, try it
you won't regret it and the dies don't cost that much.

:thumbup:

[mdm2]

I had a simular question a few years ago and was told by dillion to crimp when reloading for an autoloader, I do not crimp for my single shot pistols though but as stated above the bullet can be moved in the case easier without the crimp I hope this helps

[nevada]

I use 25.5 gr of Reloader 7. The bullets I bought have cannalures, so I crimp them with a Lee Factory Crimp Die. About the only good Lee product I've found, IF their QC guy wasn't sleeping. I like Dillons case lube, too. I use my reloads in my MAK90 and SKS, never had a problem.

[cetme]

I don't crimp and I've been doing O.K. In using up odd lots of powder laying around I've used AA1680,BL(c)-2 and H335 for target loads and all of them work O.K. AA1680 was developed for 7.62X39 and is a great choice.

[NavajoNPaleFace]

Crimping is only needed in rounds such as those to be inserted into tube magazines such as the Winchesters, Marlin, etc.

[nevada]

It can keep the bullets from being jammed back into the case as they run up the feed ramp of some guns. It also helps the powder to burn more uniformly and completely since the bullets are held in the case with essentially the same neck tension.

[Geilt]

Crimping is only needed in rounds such as those to be inserted into tube magazines such as the Winchesters, Marlin, etc.

Not 100% correct, at least according to the current wisdom. After reading what people here have said, the kind folks at Reloading Bench and talking to some folks at the range this weekend, most military autoloaders should have their bullets crimped in. Most military magazines are rather loose and don't hold the rounds snuggly in place during firing. This can cause, under certain conditions, the seated bullet to shift slightly. The result can be problems feeding the next round up and in to the chamber.

Crimping also provides just enough added resistance when firing to allow additional pressures to build up and more powder to burn before sending the bullet on its merry way. Here the result is hopefully a cleaner burn and a combination of less fouling and particulate from building up in the gas tube (AR) or piston head (AK/SKS) or, the case of direct blowback, into the recevier (G3/Cetme).

Nobody I've talked to or seen respond has said it is in any way dangerous not to crimp. I guess it really comes down to personal choice and what you have expierenced with your firearms.

[Seattlefungus]

It is dangerous in one type of weapon. As Navajo stated. Tube mags can push the bullets inside of the casing and increase the pressure at ignition to cause the rifle to explode... It has happened.. In some rounds where there is excessive room left between the powder and bullet, they will use an inert filler to keep the space constant and the powder in one location to allow proper burn.