Winchester 5.56 mm NATO FBI contract

Has anyone seen a crimp like this on 5.56mm NATO rounds?
The crimp is hexagonal and more apparent on the OTM rounds than the JSP rounds.

These are Q3313 and Q3314 from Winchester. I have read that accuracy is somewhat poor with these rounds. Maybe the crimp has something to do with it.

If the bonding process/technology on these is similar to ATK’s ‘Trophy Bonded’ pills, then that may be a reason for reports of them being less accurate than other rounds.

At certain points, the Trophy Bonded projos have had special reloading notes in various manuals or been restricted as reloading components, and the 62gr TBBC LE223T (rifle load for DEA and others) has been reported as less accurate than other common duty loads. FWIW its mechanical accuracy is still better than many of the folks behind the trigger, and at expected ranges both the Winchester and ATK bonded JSP 5.56/.223 cartridges meet or exceed most typical law enforcement ‘patrol rifle’ accuracy standards.

Variations in jacket thickness, projectile shape, etc., can make many JSP rifle loads less accurate than a competing JHP, FMJ, etc.

I’ll dig around and see what I can find on the crimp.

As a long-time competition shooter, I think I can safely say that the type of crimp has very little bearing on the accuracy of a cartridge. The 3 things that contribute most to accuracy are the bullet, the bullet, and the bullet.



I’ll add that finding the proper bullet jump before it hits the rifling is important, which I have learned has a significant effect. It’s tough to make an bad bullet shoot well and vice-versa. But what would be a possible reason for a hexagonal crimp? I can’t think of one.

Robust bullet crimps are often related to use in fully automatic weapons to prevent the recoil from loosening the bullets.

I have no idea what weapon these rounds were intended to be used in.


Automatic weapons would be my guess too, but that’s hard to reconcile with the hollow point and soft point bullets.


There is a whole thread about it here:
Apparently this crimp style appears on, among other things, Israeli M855 which would make sense for use in a Negev based on what Lew said.

Segmented crimps are very typical and found on both military and commercial cartridges. The one on the left is more pronounced than most, but not unique by any means.


To the best of my knowledge these will be used in 5.56x45mm ‘patrol rifles’…vanilla AR15/M16 variants. Not sure of the make, or whether or not the FBI rifles have the ‘fun-switch’, but I’ll try to find out.