bullet crimp or no crimp?

[remmy1100]

why is it that factory loads are all crimped yet crimping home loads is frowned upon ,crimping is supposed to produce more accurate rounds and results suggest that crimped ammo would outshoot non crimped ammo so why is it frowned upon

Edited November 19, 2016 by remmy1100

[old man]

Security of the missile in the cartridge case during recoil etc as the of best estimate of interference fit between missile and case without crimp probably 2 thou?

 

IMO, just a very light crimp is all you need for the non magnum calibers?

 

Having a cartridge come apart in the gun, not an experience to have twice?

 

Crimp die should true up the case neck so improving accuracy?

Edited November 19, 2016 by old man

[fortune]

Who are these people who are doing all of this frowning?

I just swage the neck down onto the bullet. The grip is tight enough to hold the bullet. If you crimp the case into the canalure the brass is stretched a lot more and this will lead to neck splits in quick order. I suppose from a factory point of view the bullet is fixed tighter and is suitable to be used in automatic weapons and they just want that round to be used just the once. Not for you and me to reload the case ten times or more. I've heard it said that a factory crimp makes for a more accurate round but I have never seen this as being that any better or different. I anneale the case necks and seat then swage the case down. It works for me.

Edited November 19, 2016 by fortune

[colin lad]

Always used to crimp I have stopped now and can't say I have noticed any difference to accuracy

 

Colin

[Vince Green]

The crimp is just to hold the bullet securely and as the manufacturer doesn't know what sort of rifle the ammo is going to be used in they put a good crimp on to be sure. The general view is that crimp may be slightly detrimental to accuracy but the main thing is consistency.

[Harnser]

I have always crimped my centre fire ammo . The main reason being that stalking rounds can be cycled through a gun a number of times before actually being shot . A crimp will hold the bullet in the case tighter whilst being chambered and un chambered .The lee company will say that most long range accuracy records were obtained by crimping with a lee factory crimp die .incidently any bullet can be crimped and you don't need a cannular to be able to crimp . There will be no crimp mark on the bullet after it has been through the barrel . A light crimp helps with uniform neck tension.

 

Harnser

Edited November 20, 2016 by Harnser

[Redgum]

I always crimp as said before hunting rnds can be recycle many times, also they will be in the mag when the gun is fired, on my 308 the ends of the soft points get flattened when in mag and a shot has been fired. I have never found un crimped to be anymore accurate than crimped so why not, especially with hunting ammo. Why do you think crimping is frowned upon?

[Flyboy1950]

I now use a token crimp on all my centre fire calibers.

Having had a powder release into the rifles innards and magazine you discover just how corrosive modern powders are in their unfired raw state!

I also think (though I may be wrong, as I don`t batch anneal my cases, just reload what comes to hand when I need it), that you get a uniform "Release" cartridge pressure on firing your cartridge making for better accuracy/velocity. Might be that I feel more confident with my process and that is half the battle!.

Lee also states that cartridges used for "Hunting" purposes, be full length resized, not sure about this one but I always full length resize any way, that way I can use another rifle of the same caliber and know my cartridge will fit.

 

P.

[old man]

I now use a token crimp on all my centre fire calibers.

Having had a powder release into the rifles innards and magazine you discover just how corrosive modern powders are in their unfired raw state!

I also think (though I may be wrong, as I don`t batch anneal my cases, just reload what comes to hand when I need it), that you get a uniform "Release" cartridge pressure on firing your cartridge making for better accuracy/velocity. Might be that I feel more confident with my process and that is half the battle!.

Lee also states that cartridges used for "Hunting" purposes, be full length resized, not sure about this one but I always full length resize any way, that way I can use another rifle of the same caliber and know my cartridge will fit.

 

P.

Yes bud, the corrosive bit was a real shocker to see, left untreated for a week or two would probably have caused a major problem?

[Savhmr]

Instead of guessing, I carried out some testing of non-crimped V's crimped rounds using the Lee Factory crimp, having read various opinions both in reloading manuals and on forums. There is no doubt whatsoever that using the Factory Crimp lowered both ES and SD figures, judging by chrono results, making the ammo more consistent between rounds. I took some of my .308 rounds with me to Bisley at the weekend and tried them over 600 yards, as at extended ranges, that's where variations in MV show up clearly. The crimped rounds all shot into under a 6 inch group (8mph full wind, gusting 11 and dropping to about 4mph). The non crimped did not! As most of us don't hunt at those extended ranges, where luck forms as much a part of the outcome as any "sniper" ability, it is probably of limited interest to those shooting at more sensible distances of up to a few hundred yards, perhaps out to 300 -odd. For those shooting target at more extended ranges, it would appear that there is merit in crimping because it clearly makes neck tension more consistent between rounds, and neck tension more than a few tenths of a grain in charge between projectiles, will have a larger effect on velocity. I guess it depends on brass condition too, but crimping certainly wont do any harm and, probably, can only improve consistency.

[fieldwanderer]

I found exactly the same with .22/250

 

The other thing I noted though was that if you're near the max with pressure, even a light crimp will put you over (unsurprisingly) something to be aware of.

 

No real difference in group size though at 200 yds but, then, I was getting 8-10mm groups at 100yds at that point so I doubt anything would have made any improvement.

[coyotemaster]

I guess I'll play devils advocate and say in 40 years of metallic case reloading I haven't crimped any rounds and most of my rifles will shoot .5@100 or less. They don't wear the same barrel long if they won't.

As mentioned consistency is the mother of accuracy. Annealing is very useful I attaining consistent neck tension. The more loads on a case the more work hardened the neck becomes if not annealed. I only FL size for semi autos, for bolt guns I neck size only and I believe gain accuracy via a tighter chamber fit and less case stretch alleviating trimming.

[achosenman]

I did extensive crimp testing. I always try to load to bench rest accuracy standards. Over the last 40 years I have been reloading, I have tried pretty much every fad going. There are procedures I have found that work, but equally some are just time wasters. Crimping is one of them. I tested and got the same results each time. Crimping ruins a round by introducing excessive bullet runout. Control the neck tension and crimping is not necessary. It only takes 2 thou grip to hold a bullet firmly in place. Over the many years I've been stalking with the 270, I've never had an issue with recoil loosening or setting back rounds in the magazine.

I firmly believe that most reloaders do not have the equipment to reliably measure the myriad of small variations present in home loaded ammo. Any testing we do in our back field would not stand up to scrutiny from a lab. This is coming from someone who spent in excess of £1100 pounds on a lab scale to measure powder down to the individual kernel level. Let me assure you, that introduces a whole raft of other stuff to fix regarding scale placement, environment, electromagnetic fields etc. There's a whole new World of things to fix using ultra sensitive tools...an OCD afflicted shooters delight.

IMHO we home loaders can't resist tinkering or improving, and therein lies the problem. We get an itch and just have to scratch it. I'm getting better now...honest. I'm happy that good enough will do and I don't have to continually load develop...ish. However, I have now discovered shotshell reloading, so now I have a new itch.

Atb

Edited December 12, 2016 by achosenman

[fortune]

IMHO we home loaders can't resist tinkering or improving, and therein lies the problem. We get an itch and just have to scratch it. I'm getting better now...honest. I'm happy that good enough will do and I don't have to continually load develop...ish.

However,

I have now discovered shotshell reloading, so now I have a new itch.

And you will find a lot to itch. I find metallic easy in comparison to shotshell. I have a couple of Bowmans and a 28 bore Mec sizemaster and a Mec 9000. they will all turn out very acceptable ammo but there are a multitude of things that can and do go wrong, from no primer feed so all of the powder falls out the primer hole. >> no powder or partial drop > bridging.( this results in a blooper and is potentially dangerous if the wad doesn't exit the barrel. no wad feed so the shot goes straight into the powder. Shot gets out of sync and goes all over machine & into the resize collets and the floor making a skating rink and the length of column issues. crimp adjustment ect. but when you have it all adjusted and running it is easy and the result is pretty good .

[achosenman]

And you will find a lot to itch. I find metallic easy in comparison to shotshell. I have a couple of Bowmans and a 28 bore Mec sizemaster and a Mec 9000. they will all turn out very acceptable ammo but there are a multitude of things that can and do go wrong, from no primer feed so all of the powder falls out the primer hole. >> no powder or partial drop > bridging.( this results in a blooper and is potentially dangerous if the wad doesn't exit the barrel. no wad feed so the shot goes straight into the powder. Shot gets out of sync and goes all over machine & into the resize collets and the floor making a skating rink and the length of column issues. crimp adjustment ect. but when you have it all adjusted and running it is easy and the result is pretty good .

 

Yep, I have discovered. I've been scratching the shot shell itch a fair bit recently but now I'm at the stage where I don't shoot any factory shells unless I'm harvesting cases. The pattern plate and chronograph show how poor the commercial offering are. I improved the velocity and pattern significantly with the right powder and wad to beat my "go to" RC cartridge with just 15 rounds load development.

 

For something that seems crude at first glance in comparison to metallic loading, shot shell loading is fascinating and demanding in a whole different way...I love it.

 

Atb

[fieldwanderer]

And you will find a lot to itch. I find metallic easy in comparison to shotshell. I have a couple of Bowmans and a 28 bore Mec sizemaster and a Mec 9000. they will all turn out very acceptable ammo but there are a multitude of things that can and do go wrong, from no primer feed so all of the powder falls out the primer hole. >> no powder or partial drop > bridging.( this results in a blooper and is potentially dangerous if the wad doesn't exit the barrel. no wad feed so the shot goes straight into the powder. Shot gets out of sync and goes all over machine & into the resize collets and the floor making a skating rink and the length of column issues. crimp adjustment ect. but when you have it all adjusted and running it is easy and the result is pretty good .

I too own a mec9000, when it's running right it's a sight to behold but take your eye off the ball even for a split second and it'll have you on the verge of some sort of break down!

 

I know your pain my friend 😁