Crimping

[Mike G]

Hey guys, New to reloading and am confused with crimping. I am loading 200gr N.A.B for my 300 RUM. Do I crimp or don't I ? Why crimp some and not others ? Any help would be great.

 

[mlehtovaara]

Crimping is not absolutely necessary in most applications especially rifles.

Few reasons for crimping would be
- to ensure smotth feeding and chambering
- prevent bullet setback, either when hitting feed ramp or from recoil
- ensure proper ignition of powder

It depends what application, but for a bolt action, in a harder recoiling cartridge I would put some crimp on them to be sure you have no issues feeding from the mag or with bullet setback under recoil. If you are going for accuracy and just range use feed them one at a time and no crimp.

 

[stubblejumper]

You don't need to crimp.I have owned two 300RUM rifles,and I never crimped any of my loads.It just isn't necessary.

 

[Ron AKA]

Standard rifle neck and FL sizing dies are set up to leave the neck ID 0.002-0.003" smaller than the bullet OD. The interference fit is more than enough to hold the bullet securely in place.

 

[mlehtovaara]

Standard rifle neck and FL sizing dies are set up to leave the neck ID 0.002-0.003" smaller than the bullet OD. The interference fit is more than enough to hold the bullet securely in place.

I had a .223 Savage bolt that with neck sizing and no crimp would have bullets set back when chambering as they would hit the feed ramp hard enough. I ended up putting a single shot follower in the mag in the end but was strange to say the least. These same reloads with no crimp fed in my AR no problems.

 

[stubblejumper]

I had a .223 Savage bolt that with neck sizing and no crimp would have bullets set back when chambering as they would hit the feed ramp hard enough.

The neck tension was obviously not adequate.

 

[Al-Sway]

I never crimped my .300 Win Mag, and all rounds were fed from the magazine when practicing. Every time I checked (left one round in the magazine for several magazine loads), there was no movement of the bullet. Therefore, I never saw a need to crimp.

 

[ajarmst]

I crimp if the bullet has a cannelure, I don't if it doesn't. I don't think of crimping as a matter of taste -- the cartridge and bullet design either calls for crimping or it doesn't.

 

[stubblejumper]

I crimp if the bullet has a cannelure, I don't if it doesn't. I don't think of crimping as a matter of taste -- the cartridge and bullet design either calls for crimping or it doesn't.

A cannelure offers the option of crimping,it doesn't mean that the bullet requires crimping.

 

[Boomer]

Crimping can provide a means of uniforming the bullet pull weight, particularly in applications where your rifle has a longer throat than can be reached with rounds short enough to cycle through the magazine. I've pretty much given up on seating my bullets long for my hunting rifles, I generally choose cannelured bullets and crimp.