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
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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
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.
My dies don't provide for crimping AFAIK. Haven't seen a bullet move in years of active practical rifle with a LE.
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.
hi i have never crimped any 303 reloads ( they all seem to shoot good
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.
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.
"...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.
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.Quote:
Originally Posted by Sunray
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.
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 .
No , it kind of answers the question on who crimps using 100's of people as examples . I am sure my 20 + years of match shooting every week , test firing for accuracy over 2000 rifles , building custom rifles , and my ballistic lab for cartridge development pales in comparison to your experiences ?????
Got a nice private message from old Browning with a bunch of name calling . He is a real class act . Can you get banned for name calling in a private message ? I am sorry someone with real shooting experience upsets him so much !
If the bullet doesn't have a cannelure or the case mouth is not sitting on the cannelure can you really call that crimping? that's more like tightening and the problem with that is unless you never remove the dies from your press or head then you will never get the exact same 'crimp' from session to session. You would be better served to get a die set that uses neck sizer die bushing to adjust neck tension.
I'm sure that you will find accuracy on both side of the crimp or not crimp topic. I would never dispute it because you really can't (just that simple) there are too many variables. I can tell you that even with non-crippmed reloads you can get different results if they have shot a week apart, a month, a year. In the summer and in the winter. When I first started reloading 'in the olden days' I crimped everything, after learning more I decided crimping was not necessary and to be honest I did not see a differance in APPLICATION accuracy, I was not trying to load to tight standards I mostly load for hunting and am not a target shooter.
And each rifle is going to print different, one might like a crimp, one might not, SO really IMHO the only way you can find an answer to your questions is to load and test crimped and uncripped and see which Willie Wonka Gobstopper your rifle likes.
Crimping is probably of no value for ammo used in slow-fire bench-rest or target work with bolt-action rifles.
HOWEVER, in semis, (or full-autos), it is a "good thing", because the ammo gets shoved from the magazine quite violently. Some rifles are "nicer' than others. An M1 rifle will, if in good condition, feed empty cases from the clip, straight into the chamber, without damaging the case neck. Other designs? Not so much. Furthermore, if your ammo is sloshing back and forth in the magazine with the recoil of every shot, un-crimped projectiles MAY start to move, this altering all your good work at the loading bench.
I started using the Lee "Factory Crimp" dies when they first appeared, for these reasons. Note that pretty much ALL "issue" ammo is crimped, usually at the end of the neck.
What I found interesting was that the biggest performance improvement came in a couple of "long-range" loads for .223Rem. One of these involves a compressed powder load that was showing odd variations in muzzle velocity and grouping. A delicate application of the Lee die successfully ironed that out. YMMV, and all that.
The Lee dies can be set to "just" form a crimp or form a deep crimp that will impress a substantial cannelure into a plain, jacketed bullet. In the dark ages, I had used a hand-operated cannelure-forming tool; slow and painful.
If you look at original .303 Mk7 ammo, it does NOT have a mouth crimp, but radially-impressed "stab"-crimps back along the neck. One of my shooting buddies has 're-engineered" a Lee die to replicate that style of crimps. I'll await the results.
The only problem is that every time the mouth is "folded" in to form the crimp, it works the brass pretty hard. Even with regular annealing, (and trimming!), splits will start to occur. Brass cases are ultimately a "consumable" (but recyclable) item. If you get more than ten reloads out of a .223 firing decent loads from an AR platform, or .303 from a Lee Enfield, you are doing well.
Tried crimping but gave up on that as if you have your dies set up there should be uniform tension on the neck I brought an AMP annealing machine to anneal all my cases whether F class or Milsurp as the brass becomes work hardened from repeated passing through the dies which can and does alter the neck tension plus repeated firings does not do much for them.
I ensure the inside of the necks are spotless as are the primer pockets spotless & uniformed in depth and flash holes deburred inside cases all TTL'ed to the same length.
And weighing the load to within 1-2 powder kernels of each other along with the time of day and humidity rating being as close as possible same batches of projies, primers & same cases all come to bear, I gave up weighing the brass otherwise I may as well sleep in the shed all cartridge ogive lengths for jump are measured with a comparator (Hornady comparator don't really trust the nuts.).
As rifles are all individuals so are we what groups in my rifle may not group in yours its just keep trying till you find the sweet spot for that rifle and for goodness sake change one thing at a time if you swap & change multiple things you'll chase your tail till your outside legs are longer than your inside ones.
Been there done that trust me I pretty much wore out my first 6.5 x 284 barrel chasing loads that worked with 5 different powders, 2 different primers, 5 different projies and weights/seating depths and so on ad nauseum, as we suffer shortages here in the west with all components so I had to spend nearly a year doing that, so I am only a small fry so don't flash and ash me because you think I am talking out of my freckle.
military snipers use a crimp. So as a result a crimp shant cause any issues with accuracy as long as you don't oh say, crimp so much you damage the jacket
I would love to have more detail about military snipers using a crimp. Sounds very interesting.
Until relatively recently, most snipers used the issue ball of the times. Not much "standard" ball ammo that does NOT have a mouth crimp (or in the case of .303 Mk7, stab-crimps on the neck.
The US M-21 sniper rig, (Match-conditioned M-14 with optics), was set-up for "issue" Match ammo (M118) and more recently, M-852 with the 168gn BTHP bullet. With the advent of "shooting machines" like the Accuracy International AW, etc, that special "match-grade" (Lapua, as I recall) ammo was issued as the ONLY "authorized cartridge", except in dire emergencies.
In the 1960's, the Soviets introduced "special" ammo for their Dragunov semi-auto "sniper" rifle. When the Finns "hot-rodded" a bunch of their Mosin Nagants into the TKIV series, they introduced, not just a "new" rifle, but a whole new set of ammo and bore specifications that define their "new" old cartridge, the 7.62 x 53. Essentially the same case, but with a tighter groove spec and match-grade .308" bullets. "Standard" 7.62 x 54R is permitted "in emergencies". Still in service, last time I looked, but probably up for replacement; some of the receivers are over a hundred years old.
For those looking for the "spec" of M852, see: TM43-0001-27, ARMY AMMUNITION DATA SHEETS SMALL CALIBER AMMUNITION, Section 11, page 31
He's right. Heck looking at my boxes of Sierra bullets, all Match King, no crimp grooves. When I had custom bullets made for my BR rig, no crimp groove. My stuff follows in that only the military bullets have the crimp groove. Hornady .303 and 8mm for me. My Norma 6.5x55s do not have the groove however.Quote:
Originally Posted by bob q
Admittedly, I have only shot South African military ball, in their thousands through my LE, and unfortunately too little through the last 303 Brens in SA service. Ammo dated from 1943 to 1945 in the Bren in 1972. Others dated from 1956 onwards in my LE. Never seen any kind of crimp in any of the lots. Doesn't mean it wasn't done, just that it wasn't visible.