Lee factory crimp die??
- Thread starter bunny
- Start date
Big bore dinosaur
CGN frequent flyer
- Location
- NORT OF COW.TOWN.EH
Anything with some recoil, I like to crimp.in place. Stop.the bullet from moving around in the magazine.. both my 378 and 257 bee like a little crimp.. why.. ? Because the paper says so..
Your guess is as good as mine, as to why some rifle like or dont like the CRIMP..
Same with relvovers. Dont want to lock up your pistol jumping the bullets forward.
Your guess is as good as mine, as to why some rifle like or dont like the CRIMP..
Same with relvovers. Dont want to lock up your pistol jumping the bullets forward.
- Location
- Western Manitoba
OP asked for other's experience - the post above is similar to mine - I started with 165 Speer HorCor in 308 Win in 1980's - no cannular groove to crimp into, and I only knew about the RCBS style "roll" crimp - I just relied on neck tension, and never had an issue - about 6 or 8 cartridges between 223 Rem to 9.3x62; bullet weights from 50 grains to 286 grains. I just went from there - occasionally I use Hornady bullets with cannelure groove - but many times my rifle's leade does not match to that placement - so I tend to ignore that groove, and do not crimp jacketed bullets. When I loaded cast bullets, most every one got a roll crimp into the bullet's crimp groove. A few weeks ago, I loaded 30-30 Win for first time - will be used in a tubular magazine in a Win Model 94 - jacketed bullets - will be watching to see if crimping is a necessary thing, for that - is different than I have loaded for, in the past. For my bolt action rifles, I am quite sure that some resistance to bullet pull is needed to allow the powder to build pressure when fired - but not sure that a crimp to the jacketed bullet is necessary, to do that.
I do have one under construction that might be different - 9.3x57 - based on cerrosafe chamber casts - I plan to use Jet Bullets cast 9.3 mm 285 grain bullets - is a "bore rider" - no crimp groove - I plan to use the Lee FCD on that one to snug up the case mouth to the bullet side, to cover the lube area - is no crimp groove there, on that bullet. Lee does not apparently make an FCD for 9.3x57, so part of the "construction project" is to shorten a 9.3x62 FCD for that use - to be done, yet.
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Agree. I shoot four precision 308's, and one of them shoots much better using the crimp dies, and my old 257 Roberts showed improvement as well. Other rifles it made no difference, and in one it was definitely worse. - dan
mactroneng
CGN Ultra frequent flyer
- Location
- SW Ontario
Makes setting up the dies way easier (no combination of a seating + crimp die) and offers more flexibility for the amount of crimp you put on in. Ex. for 9mm I don't even have them set to crimp, just to take the bell off the case mouth, for 500 S&W mag I crimp like a mofo otherwise the bullet in the 5th revolver shot has walked part way out of the case by the time I get to it.
Accurate Reloading forum did a test with a bunch 308 loads, overall the accuracy improved by 10%, but it wasn't consistent, some got better, others worse. My thinking is consistent neck tension means consistent internal cartridge pressures. Smokeless powders' burn at different rates with different pressures.
This has been my experience in 2 different rifles.
The first was a 32 Special Winchester 94 using H4895 and 170 gr Speer HotCor. My initial loads weren't crimped, just looking for a safe hunting load. Extreme spread and SD wasn't impressive, but in that rifle, for that purpose, I wasn't concerned.
Once I'd settled on a load, I crimped the freshly loaded cases. The next range trip showed some unexpected results over the the chronograph. Extreme spread and SD were cut in half.
Second rifle is a Tikka Varmint in 223, using IMR4895 and 75 grain Hornady Match bullets.
Again, so-so velocity consistency. I used the Lee crimp die to put a slight crimp on the case mouths. Only 1/4 turn rather than the recommended 1/2 turn. Again, major improvement in SD and extreme spread.
My conclusion is that the increased initial resistance to bullet movement makes for a more complete, consistent powder burn.
Possibly a slight decrease in accuracy at 100m, but in a long range load you need to balance that against consistent velocity and decide which you want more.
rifleman762
CGN Ultra frequent flyer
- Location
- Southern Alberta
I don't notice an accuracy improvement. Velocity goes up slightly when seating far from the lands. I think people who report an accuracy increase were probably sitting slightly below the ideal accuracy node and the faster initial burn helps get up to it.
I use my Lee crimp dies only on heavy recoiling mag-fed guns. Definitely reduces movement of the bullet in the case. I have measured this with a bullet comparator tool. Bullets were seated to identical CBTO length and then checked after being in the magazine for 3 rounds fired in the chamber.
I use my Lee crimp dies only on heavy recoiling mag-fed guns. Definitely reduces movement of the bullet in the case. I have measured this with a bullet comparator tool. Bullets were seated to identical CBTO length and then checked after being in the magazine for 3 rounds fired in the chamber.
- Location
- WMU247 near Edmonton
I crimp all my hunting rounds and anything that has some recoil that might dislodge the bullets in the mag.
I had to modify one of those Lee crimp dies for my 325WSM, I just bought a 300WSM and carefully opened it up.
I had to modify one of those Lee crimp dies for my 325WSM, I just bought a 300WSM and carefully opened it up.
- Location
- Somewhere on the Hudson Bay Coast
A situation where crimping can have a positive affect on accuracy is in a situation where the bullet has a long jump to the lands, which can sometimes occur with seating for accommodate a short magazine box and a long chamber throat. The theory is that by using a light crimp, the bullet pull weight from round to round is uniformed in a way similar to seating the bullet out close to the lands. If you're shooting 3" groups don't expect to see any change, but sometimes we do things just to make ourselves feel better and to have more confidence in our loads. Another area where it can help it if you're loading mixed brass that hasn't been annealed, or that hasn't been reloaded the same number of times.
I have a 6.5 PRC that I crimp using the 124 Hammer Hunter bullets. Seemed to reduce my groups and tighten the spread. I also load the 156 gr EOL, and for the next range trip have a few that I crimped, just to see how they perform.
Crimping for an 1895 winchester lever in 303 brit as well. This one is open sights, so hard to get an accurate reading on group size, as there is more going on, but I feel I have tightened the group as well. Plinking steel at 330 yrds with open sights is fun, in between waiting for the other rifle barrels to cool.
Crimping for an 1895 winchester lever in 303 brit as well. This one is open sights, so hard to get an accurate reading on group size, as there is more going on, but I feel I have tightened the group as well. Plinking steel at 330 yrds with open sights is fun, in between waiting for the other rifle barrels to cool.
