I am reloading 7mm Rem. Mag with Lee collet die. I use Barns TXS and Nosler BT bullets. These will be used for hunting. Lee says crimp with there factory crimp die, Barns says no crimp what do I do?
THANKS for ALL you guys HELP

If it shoots good, you don't have to crimp it. But, you'll never know if crimping will make it better. If you want to experiment, buy a crimp die and try it. My 22.250 and my 375 both like the crimp die but I haven't bought them for all my die sets.

Heavy revolver loads need to be crimped.....ammo to be used in tubular magazines need to be crimped..
Rounds to be used in a double rifle need to be crimped.....and no place else that I can think of.

I wouldn't bother crimping the 7 MM Mag at all.

one thing about crimping. you don't have to sueeze till lead comes out the nose of the bullet.

just enough for a good purchase between the case and the bullet.xd

I've been shooting a 7MM Rem Mag since 1973. I've used a crimp and not used one. The non-crimped loads shoot better. So that's what I went with in all that time they have never given me a problem and I run some pretty good loads through that gun.

I reload for several rifle calibers, using different bullets and powders and trying others all the time. Last week I tried loading 350 grain Rhino bullets in my .375 H&H over a double base powder. No crimp gave me outrageously bad deviations in velocity, with a Lee factory crimp I got incredibly good, consistant velocities. My .300 WinMag is just the opposite.

I use a Redding Body die, Lee Collet die, Lee Dead set seater, and finally a Lee FC die when reloading for my 7RM. That sequence gives me rounds that usually have less than .002 of run-out.

I don't crimp them hard like some folks, I like to screw the crimp die in until it touches the shellholder and then 1/4-1/3 a turn more. Start at 1/4 and get a feel, if the ram has no pressure at all at 1/4 move to 1/3. Any more than that presses a cannellure into the bullet. That rifle prints sub 1/2Moa groups so, crimping definitely doesn't hurt anything. I had better accuracy w/ crimped vs uncrimped loads in some rifles.

I even crimp lightly on one of my target guns and it prints ragged hole groups.

Be sure you trim your cases if you intend to crimp.

Good Luck

Reloader

I agree with Vapodog!

I only crimp handgun loads and loads to be used in tubular magazine rifles!

ALSO: On cast bullet loads not intended for pistols or tubular magazine rifles, I only apply enough crimp to remove the bell from the mouth of the case!

I don't crimp for my seven mag, (maybe should try it), but I found my .338WM shoots the Woodliegh 250gr PP better when it is crimped. I shoot Hornady 117gr SST's in my .25-06 for practice and coyotes, and found that even with the canelure on the bullet they shoot quite well with no crimp.

Just my thought but why bother crimping if it shoot's well without? Nate

What you guys are forgetting is that some dies expand the mouth more the others. Those that do benefit from crimp to get back some case tension on the bullet. A crimp is no substitute for proper case tension.

I recently did a test of crimped vs uncrimped. 300 win mag 168 gr TSX 75 gr IMR4831 10 shots each.

The crimped loads averaged 3213 fps with a SD of 6.1 and a group size of 1 3/8". The uncrimped loads averaged 3207 fps with a SD of 4.9 and a groups size of 1 1/2".

The crimped loads were a little faster and a little more accurate, but not enough to tell. My deal is that why not crimp and not have to worry about whether the bullet movement.

BTW, the crimp was with a Lee Factory Crimp Die and lightly done (leaving a little gap in between the segments).

As above , with proper case neck tension ( also known as bullet grip ) crimping is usually not required. The case neck will hold the bullet better than any crimp.


Travis F.

Crimping to compensate for poor case neck tension is just plain wrong.


Travis F.

I'm new to the game so be patient with me...BUT, if straight wall handgun cases need to be crimped, why do they sell the die set without a 4th crimping die? My understanding is that the 3rd die in the set, the seating die, crimps on its way back up...are you guys talking about crimping with a 4th die, such as the Lee Factory Crimp die?

Maybe its like asking why did GMC sell 1986 Sierras with no rear bumper...?