Do you crimp your reloads? Is there any reason to do it or not do it? I am loading for my 308 and have been but not real sure why it is needed. Does it make a difference in accuracy, or brass longevity?

Thanks,

Only for lever actions, 375's & 458's.

MM

I crimp for most everything that doesn't headspace on the case mouth.

there you have it..

Swampy is a Contra-indicator...therefore...don't crimp!

Many moons ago I discovered improved accuracy using a Lee Factory Crimp die. I've just kinda kept the habit since. I reload mainly for hunting so ensuring the bullet doesn't move is more important to me. If I was into competition bench then I suppose I would fiddle around with no-crimp and miniscule adjustments from the lands. Meh.

Ammo for the lever actions with a tube magazine and in handguns, the 38 Spl and 44 Mag get crimped. Nothing else.

Dale

Ditto on the lever actions and handguns. Also large volume cases with slow powders sometimes benefit, IME.

Factory ammo is crimped. There's a reason for that.

I only crimp for heavy recoiling doubles and bolt action rifles, and a slight taper for all semi-autos, and a medium roll crimp for revolvers and levers

Gunner

edit: still can't spel.

I usually don't crimp for TWO (2) reasons...

1) It isn't necessary in most cases since the sides of the cartridge neck are tight against the waist of the bullet and normally hold the bullet solidly in place. The possible exception to this rule would be when straight-walled cases are used to hold short, fat bullets in cartridges yielding heavy recoil such as in .44 magnum and other heavy recoiling rounds using straight-walled cartridge cases and short, fat bullets.

2) Crimping tends to raise the chamber pressure somewhat because the bullet resists moving due to the crimp holding the bullet in place in the cartridge case.

Over the 50 years of reloading I've done, these are the reasons I've read about and learned when reloading bottle-neck vs. straight walled cases.


Strength & Honor...

Ron T.

OK, what's the reason?

It lets pressure build before the bullet starts to move. This results in a more consistent burn. IMO it helps accuracy.

No crimp for centerfire ammo. I spend quite a bit of time keeping the brass straight, why would I elect to bend the mouth?
Factory ammo is crimped to accommodate a large variety of actions and knuckheads.

I used to have a Sako AIII in .30-06, nice shooter, standard load was 168 TSX's over IMR4350.. Back up load was 165 AB's over the same charge. Same primer, case, yadda yadda..

For chits and giggles, I tried out the Lee crimp on them, and it shrunk the TSX's up by half, and didn't do chit to the AB's.

Take it for what it's worth.

Swamp, the factory also chooses the powder charge, seating depth. Also chooses the trigger pull weight, lack of bedding, etc. Should we accept all those since the factory does that? I think not. We load our own and tinker with our equipment to get better results. I crimp all my pistol loads very few rifle loads and only after testing for accuracy/reliability. Doing something because the factory does shows a lack of understanding of the loading process. You should just shoot factory ammo since that is what they do.Rick.

sorry ricsmith, i just hit reply but it is not to you but to swampman500!



WTF cartridge HS on the case mouth? shoulder or belt yes and even belted cases i would HS on the shoulder.

WOW! shame on you! do you crimp bullets that dont have a canneleur? (spelling)

Crimp nothing that don't need to have it like tube feed lever actions!
NO WAY will it help your accuracy!

I dont even crimp 44mag or 357. maybe 500S$W if you think your bullets will come loose under recoil? but i doubt it?

Many pistol cartridges and some rifle cartridges headspace on the case mouth. Yes, I lightly crimp on bullets that don't have a cannelure. If you don't crimp .357 & .44 Magnum your bullets will lock up your revolver as they move forward under recoil. It helps accuracy. Slow burning powders like 296 and 110 in the .44 and .357 can lodge a bullet in the barrel without a crimp.

you meant to say rim? the back of the case,for 357 and 44M.



BADLY deforming the bullet!



you must have your taper die set too deep then.

in order to get an even crimp, you would have to trim your cases after every fireing then. so what trimmer do you use?

Very few, if any, 45ACP,9mm, 10mm bullets have cannelures on them unless they are cast. I don't know of any std die set for these rounds that does not have a taper crimp.

I crimp for revolvers and semi-auto pistols.
I also crimp for Tube Fed Lever guns, rifle and pistol cartridges.

I haven't crimped a cartridge for a bolt action rifle in 20+ years.

.45ACP, 9mm, and .40S&W, and .30 Carbine to name a few headspace on the mouth of the case. If you know what your doing a light crimp doesn'r deform the bullet and a lot of factory ammo is crimped even though the bullet has no cannelure. I trim .44 and .357 magnum once and forget about it. You need to find someone to help you. I've been reloading since 1965 and I'm 55 years old. Reading the info parts of a good reloading manual is a good place to start.

i did think of them but we're in the big game rifle section.


fine, your choice to, i never crimp .40- 38/357

tube fed yes!

dream on! I guess old habbits are truely hard to break?

shall i post all my first-second and third match winning stickers for you?

go ahead and keep crimping away LOL....i been loading for over 30yrs too

if you dont keep them trimmed, how in the hell can they be anywhere near consistant when you crimp them?

i think i'm better off talking to the wall.

Your responses make me think you were new in the hobby. If it's working for you then well enough. I shoot things other than paper so I need reliable guns, ammo, and accracy.

I don't even crimp the .460 Weatherby, it is not necessary unless you have a set of sloppy tolerance dies that do not fully size the necks.I also dump bad dies fast and rebuy a new set until they are right.

I do crimp some of the straight sided cases but that is for feeding purposes only.

again, you're so funny LOL

proof is on the paper

dont forget to click on the link of whitetails that didnt show up for some reason.

It's way beyond a hobby for me! I've crop damage shoot whitetails and have many many that aren't paper.



I think i am done arguing with someone who obviously has been figured out.

a few practice groups at 700yds and as exped to be the lower 3 shot group is 900yds (practice)


i hit groundhogs so far away i have to take a dog to find them, and i avg @ 100/year

A die doesn't have to be defective in order for a bullet to shift in the case from recoil. I regularly reload for 7-8 different calibers, and I crimp just about everything with Lee crimp dies. Let me be clear: I'm not suggesting that it's absolutely necessary, but I reject the notion that there's no value in it.

I've never understood why crimping generates such a viceral reaction from people. I'm not even going to make the consistent ignition pressure argument, but let me make a case that I can support with empirical data (and a set of calipers): Under heavy recoil, bullets can -- and DO -- contact the front wall of the magazine box due to the rearward inertial of the rifle, and they then can -- and sometimes DO -- push further into the case because of the resultant force. This changes OAL, and, if you've done any serious load development, you know that even 0.005" of OAL can have a dramatic effect on accuracy for a given load.

I defy anyone to prove to me that crimping REDUCES accuracy. So, if crimping simply guards against a shift in bullet depth from high-recoiling rifles, what's the problem?

Seems we need a very good consistent shooter to load 10 with a crimp and 10 without. Shoot each ten for a group and we'll get an idea whether accuracy is affected or not.

an AR would be another round worth crimping if you had any feeding issues.

but the original question to this topic, wich many opinions seem to forget as the post rolls on......
from Robc



i would not crimp it unless it is a tube feed.

you posted the same time i wat trying to type.



there ya go....let us know what you found out!

I have yet to hear one single 1k bench shooter say "i crimp my bullets"

I crimp for levers and handguns.

I have never crimped for my 30-378 378 416 and 460 Bee mags.

You wouldn't want to base anything on my shooting. I want to make kill shots on whatever I shoot at but to shoot 1000 yards, I'd have to shoot across 2 or 3 ridgetops or drive west.

Started loading in 1965 and you are 55yrs old? Started loading when you were two years old!!!! Wow, I am impressed. Most kids that age haven't learned to read.Rick.

what gun are you shooting? bullet? powder? brass? primer?
magazine fed? If it is factory gun, I would FL size your brass and fire once, measure your headspace of a fired round and "BUMP" the shoulder back .002-.003 to size your brass to your chamber. If you have a HS tool? If not, slowly FL size your brass slightly more each time until it just chambers easy enough that you dont have to work the bolt hard. AKA bumping back just enough to put less stress on the brass and fit your chamber.
follow me?
now your brass is sized just right, clean the lube off! or trim with it on like i do with my wilson
trim .010 from max length listed in manual (not necessary every time maybe 3-4th, square mouth is more important than length as long as it is not too long.
prime
I always from there select a reputible powder for the bullet shooting and work up with a crony to find max! then back off at least 1-2gr then play with seating depth for best accuracy.

neck tension is the next subject that i go for (the button that is pulled back through on the up stroke)

brass of different makes have different thicknesses! I select a brass that has .002-.003 of bullet release room!
measure a loaded round then a fired round. or you can controll that with neck turning. or a die like redding bushing dies.

i'll stop there for now

or maybe seampman700 with his hunting expertise can tell you the rest?

Benchrest guys shoot 12 lb rifles that don't recoil. They also don't feed their guns from a magazine. Next argument?

That would be good, assuming the test rifle was accurate enough to be considered a test rifle. And, the ammo was consistent enough for the resultant data to not be lost within the margin of error. What caliber would it be? How many rounds would we need to prove the point? It would have to generate sufficiently high recoil so that there was enough inertia to create the effect I'm talking about. Sounds like a lot of work. Who would shoot it? How would we know that they could shoot well enough to validate the results? Only the factory has the proper equipment and controls...but wait...they do crimp, don't they???

How about those of you who laugh at crimping just chew on this postulate: Changes in OAL can (and do) have a measurable effect on precision (this is beyond dispute). Blunt force, applied to the tip of a bullet from the magazine wall of a heavy recoiling rifle can drive the bullet into the case, thereby changing OAL. This is why your lead tips get smashed up, by the way; we can debate how much force this takes, but not that it does or does not occur. A crimp, if properly applied, can definitely retard the tendency of a bullet to shift in response to such a force. It's a mechanical lock. Seems like a reasonable control mechanism to me.

Thus, those of you who don't crimp, and have never needed to, likely wouldn't know if you would benefit from it or not. Being blissfully unaware does not disprove the efficacy of a procedure, no more than not wearing a lifejacket proves that they aren't necessary (because you haven't yet drowned).

I think I'll just leave my dies like they are for now. I put bullet in, aim at deer, pull trigger, gun goes bang and deer falls down. Yep, it's all OK.

sorry, friendly reply to richard (seriously, my typing may sound harsh but i don;t sugar coat it) it is NOT ment to be harsh it is just my reply and typing.



don"t recoil? DUH, complete BS! now we're defying the laws of physics

no magazine, exactly! so it is bullet in chamber

why don't they crimp it then if it gives better accuracy?
It dont! or the top shooters would be doing it, don't ya think?
maybe you should crimp a few and go to a santioned match?

I will go with tube fed and AR's and maybe some handguns but BS on the accuracy thing.

it would be there strictly to hold the bullet in place if needed.

I never said that crimping gave better accuracy (we're actually talking about "precision," not accuracy). My point was that crimping didn't degrade precision (in my experience), and it has other positive attributes in that it prevents bullets from slipping in the case neck under recoil and from their impact with the front of the magazine wall (in heavy recoiling rifles).

People tend to dismiss crimping as a fool's errand, but you're making my point that a lot of folks don't understand that it has purposes other than its effect on shot precision.

As to the benchrest thing, what I said was correct. Of course I didn't mean ZERO recoil, but there's no appreciable recoil in your typical benchrest rifle -- certainly not enough for the inertial effect of which I'm speaking to matter. Besides, you'd have to have rounds in the magazine (not the chamber) in order for the bullet to be pushed into the case by contact, and BR shooters load their rounds one at a time, directly into the chamber.

no problem, but to crimp a 308 winchester round still wouldn't make sense to me unless it is tube fed or in an AR semi platform

i have hammered 308 win bullets and case friction is plenty.

we still don't know what rifle or bullet rob is using ?

to really answer the first question,I think we can all agree on that?

My rifle is a Winchester model 70 and I have been loading Hornady 150 and 165 BTSP interlocks with 42 and 44 grains of 4064.

And thanks for all the replies, I appreciate them.

The most reasonable explanation I have read on this thread !

Your math isn't worth a $hit.

Nothing like a bunch of dumb [bleep] paper shooters that seem to know almost nothing about reloading, cartridges, or headspacing. In the real world we need reliability. Buy a reloading manual and read it from the begining.

"It's common for crimped bulets to produce more consistent powder burn when using smokless propellants."

I try to respect everybodys opinion...but

The responses showed little knowledge of how powder burns or how some cartridges headspace. All this info is in the begining section of an inexpensive reloading manual. Failure to crimp with some powders will result in bullets lodged in the barrel which can ruin a gun or injure/kill somebody.

The responses showed a few members entering into a battle of wits with the unarmed....

Always carry a good hardwood dowel,lard and a small hand sledge to the range, it comes in handy for those dangerous half azz boolits that don't leave the bore!

I crimp everything. I love to crimp!
I'd crimp your crank if I could get the little thing in my press.
Cisco

I do not always Crimp,

But when I do, I use Lee Factory crimp dies (except for my 480R)

I Do crimp:

All Handgun ammo

and

All AR10 & AR15 Ammo

And

All Levergun ammo

Never any Bolt action ammo or BAR ammo

I'm not against doing it... I just don't

That is all

Snake

Please explain.

Chirp, chirp...

Could you let us know specifically which load that would cause that phenominum !!

I'm with temmi on this one. I crimp handgun, anything in a tube feed, or semi-auto. Anything bolt action does not get a crimp. Lee crimp dies are all I use when I do crimp, best thing since sliced bread IMO.

That is because you are both wise and experienced beyond your years Fotis. I concur. Also agree with a previous post that bench rest shooter and long range shooters would never consider it but listening and advising are mutually exclusive. The advice is there for those who want it.

A bullet lodged in the barrel is a dangerous situation!!
For our safety we're still waiting for those loads that'll stick a bullet in the bore if not crimped

NRA High Power shooters have known for a long time--1960 or so--that crimping has a slight but negative effect on accuracy. This is because the crimping pressure variation is just one more slight variable. The only valid reason for crimping, in my experience, is if the bullets slip in the cases due to recoil in the magazine. Whether the rifle is a semi-auto or not makes no difference that I can tell. Unless your sizing dies are incorrect, crimping is not needed for anything in the 30-06 or .300 magnum class.

I do not crimp .375 H&H 300 grain 2500 fps soft point loads because I need to seat them slightly deeper to get them to feed well. The bullets do not shift in the cases. I do crimp 300 grain solids because they have many little grooves, not just one cannelure.

I get a kick out of the "debates" that materialize on most forums lately. People seem to be thinking their opinions are what should be accepted and none other's matter. I've been reloading for about 40 years now. I crimp 30-30 Win and ONLY when it is going into a tubular magazine. For the purposes of this discussion, who gives a flying [bleep] WHAT you do with handgun reloads? More and more people are showing up here that just what to see their,,,,,,,,,,,,,,aw nevermind. It just isn't worth it.

That's pretty much what I do as well. Also over on Accurate Reloading, there is a good treatise on crimping vs non-crimping bullets and the results showed a slight improvement in accuracy when a uniform crimp was applied and that is why I use it. For doubles, there is also some good info in Graham Right's book on the subject and he comes to the surprising conclusion (at least to me) there was no need to crimp even the biggest doubles. Also there is a note in there about the 416 Rigby magazine rifle where no amount of crimping prevented at lest some dislodging of the bullet. Lastly, do the opposite of whatever that inbred doofus Swampdick says to do. jorge

Back in the early 80's I was loading for a Win 70 Featherweight .308 win using 165gr Horn BTSP's and used a slight roll crimp at the cannelure. That particular load of BL-C2 with ww brass, and win primers shot ridiculously well.

Was young and dumb in those days and never tested without the crimp. But because of how well it shot, I just kept crimping them.

Again, I used a slight roll crimp. You should try it and see how it works out for you. I never crimped any bullet that did not have a cannelure though and today I don't crimp at all.

That was one of those rifles I wish I never sold.....