Crimping question

[Grimstod]

I was thinking about running this experiment myself but thought I would ask first incase someone here has already done it or knows the answer. By the way I would rather not do it at all since I worry about getting the bullet out of the barrel.

So this was the plan. Load 3 rounds with NO POWDER just primers and bullet.
1. Crimped heavy
2. Crimped medium
3. No Crimp at all.

Would the bullet stay in the shell with either of the crimped examples? I have a friend who adamantly preaches that crimping your bullets keeps them in the shell till the powder starts burring. I am skeptical of this line of thought especially since he uses Magnum primers. ??? What do you guys think?

 

[jo191145]

There's a multitude of variables that would make such a test inconclusive.
Your friend is at least partially correct. Generally speaking a crimp will force the bullet to stay put longer than no crimp. That's just simple mechanics. Wether or not the primer can overcome the crimp is fairly irrelevant. And wether or not that's of value to any particular shooter is once again a multitude of variables.

That being said I've fired a few primer only loads in my day. Never had much trouble backing a bullet out of the bore. Primers won't drive them that deep anyway. Half the fun of this hobby is testing things to find your own answers.

 

[Grimstod]

How did you push the bullet back out of the lands? Cleaning rod? Or wood dowles? Or something I havnt listed.

 

[Witchhunter]

Don't ruin your 40 dollar Dewey rod. Go to a welding shop and get a piece of brass brazing rod, just smaller than your bore. If you have a barrel that is longer than the rod, just drop it down the bore a couple of times, it will kick a stuck bullet loose. This also comes in handy when you seat into the lands and eject a case full of powder only!

 

[effendude]

I was thinking about running this experiment myself but thought I would ask first incase someone here has already done it or knows the answer. By the way I would rather not do it at all since I worry about getting the bullet out of the barrel.

So this was the plan. Load 3 rounds with NO POWDER just primers and bullet.
1. Crimped heavy
2. Crimped medium
3. No Crimp at all.

Would the bullet stay in the shell with either of the crimped examples? I have a friend who adamantly preaches that crimping your bullets keeps them in the shell till the powder starts burring. I am skeptical of this line of thought especially since he uses Magnum primers. ??? What do you guys think?

When does this friend think the bullet starts moving? It moves because of the expansion of the gases breated by burning powder which is lit by the primer. If the primer moved the bullet, we wouldn't need gunpowder, just hotter primers and shorter cases. Sounds like your friend likes to share his "expertise" on matters that don't really.....matter.
Scott

 

[Raythemanroe]

Primers send them down the tube a good ways.. Some .22 rimfires are just small primer compound and a .22 bullet..



Ray

 

[jo191145]

I was thinking about running this experiment myself but thought I would ask first incase someone here has already done it or knows the answer. By the way I would rather not do it at all since I worry about getting the bullet out of the barrel.

So this was the plan. Load 3 rounds with NO POWDER just primers and bullet.
1. Crimped heavy
2. Crimped medium
3. No Crimp at all.

Would the bullet stay in the shell with either of the crimped examples? I have a friend who adamantly preaches that crimping your bullets keeps them in the shell till the powder starts burring. I am skeptical of this line of thought especially since he uses Magnum primers. ??? What do you guys think?

When does this friend think the bullet starts moving? It moves because of the expansion of the gases breated by burning powder which is lit by the primer. If the primer moved the bullet, we wouldn't need gunpowder, just hotter primers and shorter cases. Sounds like your friend likes to share his "expertise" on matters that don't really.....matter.
Scott

Primers do indeed create expanding gases and move normal bullets out of the case. That's a given. My biggest question would be if you could stop that from happening not just slow it. Never tried to stop a bullet from moving. That might be interesting.

Edit
Now that I think back on it I have had some that needed to be pulled so I guess it would be fairly easy to overcome that pressure intentionally.

 

[Grimstod]

I have pulled bullets crimped and with no crimp. Never really felt a diferance in the amount of force necesary on my Forster Collet bullet puller. I really don't think that crimping would keep the bullet in the case no matter how hard the crimp was.

As a side not there is also this theory (that my friend also ascribes to) that there is a delay between when the primer goes off and when the powder burns. Personally I think it's pretty much a seamless explosion. But I am not an expert on this.

 

[Raythemanroe]

I have heard wolf primers may a bit slower.

 

[Webster]

I tried to post something earlier and apparently didn't save it.

Where does your expert friend get his info from about crimping improving group size? I assume you’re talking about rifles not pistols. Does he compete at a high level of competition? Sounds like they are just thoughts that he has without any proof. Some people think that if something makes sense they assume it’s correct. There are a lot of metallurgy statements on this website that are completely incorrect.

No one shooting bolt action BR guns in competition crimps bullets. Groups under 3" are being shot at 1000 yards without crimping. They are shooting 50 shot aggregates around ¼ MOA at 100 & 200 yards combined without crimping. Neck tension was good enough for my Rem 7mm Mag magazine rifle. I didn’t have bullets getting pushed into the case from recoil. If a rifle bullet has crimping grooves it is not intended for accurate varmint hunting or competition. It’s a big game hunting bullet or for a tube magazine rifle.

There are at least ten other things to worry about making good ammo. If you don't have a quality rifle, good bench techniques and wind reading ability its hard sort out loads. Have your friend shoot 3 5 shot groups same load and see the difference in group size and judge for yourself how expert he is. With the same good load I cannot shoot close to the same group size every week. I don’t have good bench skills. My rifle is a 6BR Norma hunting varmint rifle that shoots groups close to 1/4" all the time. Bad loads are always under ½”. The biggest area for improvement is the shooters skills. You can have the best ammo and never shoot small groups if you are not aware of everything you are doing at trigger time. You need to recognize areas that need improvement and work on them.

 

[2506]

If you have a bench rest target rifle with everything as perfect as it can be made then crimping probably will not help at all and CAN be a determent to accuracy. But I have done extensive trials with many old military rifles and have found that using a Lee Factory Crimp Die with a medium crimp usually increases their accuracy compared to the same load that is not crimped. Most of these rifles have loooooooooooog throats and you can't usually get a bullet in a mile of the lands with a round that will work through the magazine. It is my thought that the crimp holds the bullet that nano second longer in the case to allow the pressure in the case to build up just like the bullet that is loaded close to the lands will be retarded a nano second when the bullet hits the lands before the base leaves the case. It is just my thoughts but the proof to me is in the difference in the accuracy I get in MANY different rifles and calibers. The only rifles that I have not seen this happen with are the Swede Mauser 96 in 6.5X55. I could tell no difference between crimped and not crimped loads in four different rifles. They all shot very well. By the way I have cleaned the plow of many a bench rest rifle shooter in the vintage military rifle bench rest matches we used to have at our range. They all were strongly convinced that using a Lee Factory Crimp Die with match bullets would destroy the bullets accuracy. I kept using the crimp die and kept walking away with the first place prize. ;D

 

[Webster]

I have no use for old military rifles. I need a rifle that can hit a GH to at least 400 yards first shot.

 

[Grimstod]

If your barrel has so much free bore then it's time for a new barrel. I have several surplus guns. If I can't get the bullet in the lands then it gets a new barrel or it gets put behind glass.

Interestingly I have had the opposite experience at surplus rifle shoots. Over at socamo.com everyone crimps. And no one there has ever even come close to out shooting me. They scratch their heads and wonder why I get a gun to shoot so well and I tell them they need to start their load development in the lands and STOP crimping. So far only two have fallowed my advice. Their groups halved in size.

 

[GrocMax]

I thought cannelures and crimps were protection from being dropped out of airplanes to troops on the ground? Do they serve any other purpose other than rough handling protection?

 

[Grimstod]

No I would say you got it right. Just for ruff handling.

 

[bow shot]

Rough handling precuation for sure (hunting, battle)... but I have no background intel... just memory. Came up kinda dry googlin', lol!

 

[searcher]

While a bit ambarrassed to admit - I had missed powder charging a few .45 acp cases when first setting up a Dillon machine about 20 years ago. The primed and empty of powder cases had the bullets heavily crimped (rol-crimped I believe). each of them (not collectively) made it about 3/4 of the way down the 5" bore.. While never having done this with a rifle, nor magnum primers, I would think a crimp of any type would have little effect in containing the bullet within the case.

 

[Grimstod]

While a bit ambarrassed to admit - I had missed powder charging a few .45 acp cases when first setting up a Dillon machine about 20 years ago. The primed and empty of powder cases had the bullets heavily crimped (rol-crimped I believe). each of them (not collectively) made it about 3/4 of the way down the 5" bore.. While never having done this with a rifle, nor magnum primers, I would think a crimp of any type would have little effect in containing the bullet within the case.

Very good info Searcher. Thanks for sharing your experience.

 

[fguffey]

Neck tension? I can not measure neck tension, I can measure bullet hold.

Then there is 'time as a factor' as in the delay when releasing the bullet with hold. Again, I do not know how many tensions it takes to hold a bullet, I can measure the numbers of pounds necessary to move the bullet out of the case. Back to time as a factor, when the primer is struck it only takes milliseconds for the pressure to push the bullet into the forcing cone.

Minimum/maximum amount of bullet hold, with the best of crimps the bullet will leave the case, the pressure required will be a small window of time. R. Lee in his book on modern reloading wrote a short section about the benefit of a crimp, I will assume no one read the book.

I do hear a lot about the most powerful primer brand, if I was interested I would use different primers in cases with no powder to see which primer drove the bullet into the forcing cone the furthest. I do not use R. Lee as a good source when determining 'the most powerful primer', Federal did not donate primers to be tested, in his book, R. Lee said he did not test Federal primers because they did not donate primers to be tested.

F. Guffey

 

[bow shot]

I should have added this: for rifle its about rough handling.

However, as I understand it for straight wall (ie., namely pistol) stuff, I'm pretty sure its a mandatory thing?? Not an expert there...