I've read alot of posts on crimping, but they always refer to handguns. What are the reasons to crimp for a bolt action? I've read it is more accurate. is this true? Is there any reason why not to crimp? I'm wondering about the 270- 30/06 cartridges in particular, but reasons for others would be appreciated as well. I notcie all my factory loads are crimped. why?
crimping for bolt actions
- Thread starter bruno
- Start date
I personally think that crimping for rifles is only necessary on the big guns, African type rifles. I also think that not crimping is more accurate, but that's just my opinion. I don't really hear about bench rest shooter crimping their handloads. For 270 / 30-06, it's not necessary. But like you said, others feel that it improves accuracy.
One of the main reasons to crimp the cartridge is so that the bullet is securely held by the case. That way when the gun is fired, the recoil will not not change the cartridge length.
Under heavy recoil, the bullets in the cases in the mag tend to stay in place while the case moves backward.
Under heavy recoil, the bullets in the cases in the mag tend to stay in place while the case moves backward.
I never crimp, but my target rifles are all single shot, single load. Never had bullets fall out when loading for my .300WM hunting rifle either. If I was shooting something heavier I might crimp.
A far as accuracy goes, your hunting rifle may not know the difference on game size targets. I am with Scott N on this one.
A far as accuracy goes, your hunting rifle may not know the difference on game size targets. I am with Scott N on this one.
The Below is a shamless plug for LEE Precision LOL.
If you can get consisitent neck tension with out crimping, can be sure that chambering the round does not set the bullet further into the case and would like to buck the collective knowledge of the firearms industry that mostly puts crimp grooves on thier bullets then don't crimp.
For accuracy you must have consisitent pressure and neck tension/crimp plays a big role in this. For finger loaded BR guns not so hard to accomplish for mechanically loaded repeaters a consisitent crimp is your friend.
Load your rifle with your uncrimped rounds fire one then cycle the rest through the action twice then fire another with them back in the magazine. Measure the rounds you have left and see what happened. Depending on neck tension etc all might be well or you might have reduced or increased OAL.
For the 15 bucks it costs a LEE collet neck sizer sure makes for some consistent rounds that will handle a pile of push/ pull with no bullet movement or change in start pressure.
I have played around a bit with crimping and a chrongraph and unless using brand new Lapua brass I found FPS variations decreased dramatically when rounds were given a consitent crimp.
P.S The deer wont ever know or care if you crimped or not, he probabley wont even notice if your bullet is going 50FPS faster or slower when it leaves the muzzle
enjoy
If you can get consisitent neck tension with out crimping, can be sure that chambering the round does not set the bullet further into the case and would like to buck the collective knowledge of the firearms industry that mostly puts crimp grooves on thier bullets then don't crimp.
For accuracy you must have consisitent pressure and neck tension/crimp plays a big role in this. For finger loaded BR guns not so hard to accomplish for mechanically loaded repeaters a consisitent crimp is your friend.
Load your rifle with your uncrimped rounds fire one then cycle the rest through the action twice then fire another with them back in the magazine. Measure the rounds you have left and see what happened. Depending on neck tension etc all might be well or you might have reduced or increased OAL.
For the 15 bucks it costs a LEE collet neck sizer sure makes for some consistent rounds that will handle a pile of push/ pull with no bullet movement or change in start pressure.
I have played around a bit with crimping and a chrongraph and unless using brand new Lapua brass I found FPS variations decreased dramatically when rounds were given a consitent crimp.
P.S The deer wont ever know or care if you crimped or not, he probabley wont even notice if your bullet is going 50FPS faster or slower when it leaves the muzzle
enjoy
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I dont crimp my rifle shells . When I load for my 300WSM , I can damm near put all my weight on that bullet and it will not move at all, an I have one hell of a time trying to pull one out as well . I usually make a couple of dummie rounds for what I am loading for and give them a few hard taps and nothing ever moves .
BigUglyMan
CGN Ultra frequent flyer
- Location
- New Scotland
This is why you crimp. The various stages of being driven back into the case under recoil. They are 350 grain Barnes X in a 416 Rigby.
BigUglyMan,
I had some trouble with TSXs seating loose in .257 Weatherby, .308 Winchester, 30-06 , 7mm STW, .375 H&H and .416 Rigby. In each instance I polished a thousandth off the expander ball and now they hold like grim death, with or without the crimp. This gives 3 thousandths of neck tension. It's almost like the TSXs are undersized, but they mic out perfectly.
I had some trouble with TSXs seating loose in .257 Weatherby, .308 Winchester, 30-06 , 7mm STW, .375 H&H and .416 Rigby. In each instance I polished a thousandth off the expander ball and now they hold like grim death, with or without the crimp. This gives 3 thousandths of neck tension. It's almost like the TSXs are undersized, but they mic out perfectly.
257Roberts
CGN frequent flyer
- Location
- Peterborough ON
I agree with dizzy dan.
I also crimp everything and the Lee crimp dies are so easy to use. You can adjust them for a light or heavy crimp.
257 Roberts
I also crimp everything and the Lee crimp dies are so easy to use. You can adjust them for a light or heavy crimp.
257 Roberts
DOGleg - How did you polish the expander ball? I have tried varous things on it when chucked in my drill and have not been able to touch it.
As for crimping, unless it is a real heavy bullet in a powerful round, it is not required.
If rounds are in and out of a mag, they can get battered and pushed back. In a hunting round I would do it for a different reason. I would not want a case mouth hanging up on chambering.
I run police and hunting ammo through a taper crimper to make sure nothing is sticking out.
As for crimping, unless it is a real heavy bullet in a powerful round, it is not required.
If rounds are in and out of a mag, they can get battered and pushed back. In a hunting round I would do it for a different reason. I would not want a case mouth hanging up on chambering.
I run police and hunting ammo through a taper crimper to make sure nothing is sticking out.
"...a case mouth hanging up on chambering..." That'd mean something else is terribly wrong. Like not having a bullet.
Crimping isn't required for any rifle round except heavy recoiling cartridges and those used in lever actions. Case neck tension should be enough on everything else.
A taper crimp on a pistol cartridge, like a .45 ACP, aids feeding. It's not needed on a rifle cartridge. Rifle cases don't get 'belled' so there won't be anything sticking out.
Crimping isn't required for any rifle round except heavy recoiling cartridges and those used in lever actions. Case neck tension should be enough on everything else.
A taper crimp on a pistol cartridge, like a .45 ACP, aids feeding. It's not needed on a rifle cartridge. Rifle cases don't get 'belled' so there won't be anything sticking out.
Ganderite,
I polished them in a drill, just like you tried. The trick is to use a no nonsense metal cutting sandpaper or emery cloth and squeeze it hard. Measure as you go with a mic or just a dial caliper. I've got piles of sandpaper left from when I made knives, Hermes and Klingspor stuff.
I polished them in a drill, just like you tried. The trick is to use a no nonsense metal cutting sandpaper or emery cloth and squeeze it hard. Measure as you go with a mic or just a dial caliper. I've got piles of sandpaper left from when I made knives, Hermes and Klingspor stuff.
- Location
- Somewhere on the Hudson Bay Coast
I crimp everything regardless of caliber provided that there is a cannular cut into the bullet. Proper crimping might actually improve accuracy by uniforming the bullet pull weight, and in powerful rifles, it certainly prevents the bullet from being driven back into the case. Crimping makes your ammo just a little bit better and takes little effort. I am astonished how many people refuse to take advantage of, or even acknowledge the benefits.
Like most things, crimping can be done incorrectly. Done improperly, crimping cannot have positive effect on accuracy or terminal performance of a bullet if the bullets are being deformed during the crimping operation.
Like most things, crimping can be done incorrectly. Done improperly, crimping cannot have positive effect on accuracy or terminal performance of a bullet if the bullets are being deformed during the crimping operation.
