Reloading question

[RobD]

What are the merits of crimping .303 reloads?
Specifically, does crimping make the ammo significantly more accurate?
I haven't crimped any of my rifle ammo for years, but I would be interested to hear what others do.
Rob

Information

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[Strangely Brown]

I apply a light crimp to make my ammunition more uniform, started doing it with 7.62mm and noticed marginally smaller group sizes although to be fair I can't say I notice the same for my .303 reloads.

[Daan Kemp]

My dies don't provide for crimping AFAIK. Haven't seen a bullet move in years of active practical rifle with a LE.

[Parashooter]

The classic benchrest/target answer: for accuracy, eliminate variation. Crimping introduces an added variable and is therefore omitted when not needed for feed/recoil/handling issues.

[pisco]

hi i have never crimped any 303 reloads ( they all seem to shoot good

[S-A-M3]

I have been reloading for mostly 303 for about 30yrs In my experience, 303s like uniform neck tension ,one way to achieve is to crimp the case!!So just carry on what you are doing, 303s for some reason are very touchy to different powders,so effecting the point of aim. SAM3.

[Bindi2]

I have a Lee crimp die in the last station on my Dillon press it tightens up the group (even neck tension) stops projectiles moving out of the case when the bottom of the magazine is never reached because it is always getting topped up. Crimping for me took out the variables and gave accuracy in well used battle rifles. The HTs and Ts show the same tendencies adjusting the die while testing showed some very interesting things. My go to work rifle is a No5 has to be crimped just like the Military Ammo.

[Sunray]

"...crimping make the ammo significantly more accurate?..." Nope. A crimp is detrimental to accuracy. A crimp does not make anything more uniform either. A crimp is only necessary in heavy recoiling cartridges and those used in lever actions.
Milsurp stuff was crimped because it may have ended up in an MG.
"...My dies don't..." It'd be unusual if they do not. It kind of like neck sizing with FL dies. Doable, but it takes some trial and error fiddling. Certainly isn't something to worry about either way though.

[Micheal Doyne]

" A crimp is detrimental to accuracy. A

This is an interesting statement, I have found with my own reloading that all my lee enfields (and other .303s) group tighter with rounds that have had a light to medium crimp applied. I use lee dies, neck-sizing only on brass dedicated to each rifle and a lee crimping die. This improvement may be only due to another limitation in my rounds however I think as a blanket statement there significant evidence to the contrary in a number of instances.

I have had good groupings in the past with rounds un crimped and with almost no neck tension, however this was only when the rounds where loaded singlely and great care was taken during storage and handling not to disrupt seating depth. In general I found this to be impractical, as typically one or two in the group would be disrupted. Over all the best consistency I have achieved is with a light crimp.

[bob q]

Crimping can be a "crutch " to poor quality handloads . But if you have good quality , matched components crimping never helps accuracy . I have been match shooting for over 20 years . Everything from national level benchrest to sporter class and old military rifles . None of the shooters in BR or the best shooters in the others ever crimped anything .