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Posted: 1/10/2009 5:49:41 PM EDT
| How many people crimp their .223? I just bought 1500 rounds of 62gr. FMJ without the cannelure. I know the cannelure's primary purpose is for high recoil and automatic weapons just like the crimp on the primer. Being used in an semi-auto AR, is it really necessary? |
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The subject comes up, most every week. My canned answer...........
To crimp or not? www.scidetroit.com/bulletseating.htm ________________________________________________ Re-loading Crimp or Not More reading on crimps...... Q. The rifle bullet I'm loading has a crimp groove, but the cartridge length recommended puts the groove out of the case. Should I change the seating length to make the crimp groove line up. A. No. Not all rifle cartridges require crimping. The groove on the bullet is positioned for those that need the crimp. If the recommended seating length puts the crimp groove above or below the case mouth, we determined that crimping was not needed. Having the crimp groove above or below the case mouth has no adverse effects on accuracy or performance. –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Q. I'm reloading 30-30 ammo for my lever-action rifle. Do I need to crimp the bullets. A. Yes, crimping is mandatory for ammo to be used in any rifle with a tubular magazine. The pressure of the magazine spring and the vibration of recoil can cause the bullet to "telescope" into the case, resulting in poor feeding and increased pressure. When loading for a tubular magazine rifle, always select a bullet with a crimp groove, and one that has a flat point to prevent in-magazine firing. –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Q. I bought a reloading die set and there’s a note with the dies that says something like, “Speer does not recommend using their bullets with these dies.” What’s the deal? A. Speer never made such a broad recommendation. Speer’s recommendation is: Do not apply a crimp to any bullet that does not have a crimp groove. The die company in question markets a die to produce a “factory crimp” and recommends it be used on any bullet. Speer’s tests, and those by another bullet maker and an independent gun writer, show that crimping a bullet that doesn’t have a crimp groove degrades group size by an average of 40 percent. Other than the crimp die, we have no problem with our bullets in that firm’s dies, although our preference is for RCBS® products. We express ours thanks to the die maker for allowing us to make contact with so many new SPEER customers. Taken from....... www.speer-bullets.com/default.asp?s1=5&s2=30 And……….. The military specs a crimp for the reasons of: Prevention of bullet set back. They don't want bullets that will telescope back into a case and cause a jam or overpressure condition. Not, to mention that the ammo goes through a lot of "abuse." Uniformity of ammunition is key to consistent functioning for a firearm (especially for semi auto and full auto use). ________________________________________________ For us "civilian shooters" it isn't written in stone, that you must or not, crimp. For a new re-loader.........may I suggest that.......... If the bullet has a cannelure.......then, crimp it in the groove. IF the bullet doesn't........then, just use enough neck tension. "Enough," so that the bullet isn't damaged by seating and/or crimping and doesn't telescope back into the case (or fall out). Once you have more experience.........do what you like. And, try experimenting a little with COAL. Just my .02. Aloha, Mark |
| I,ve Taken to crimping all of my semi auto loads. I use bullet's with and without a groove. I have noticed more consitant velocity's with a crimp. My accuracy in some case's has improved. It has not proved detrimental to any of my loads for my AR or M1A or Garand. The reason I started is because I have experianced bullet set back in my rifle's without a crimp when feeding from the mag. Bolt's seem to push on bullets pretty hard when stripping rounds from a loaded mag and slamming them up the feed ramps. Since crimping I have less of the "Did I somehow put to much powder in that one" Question's when clocking my loads and seeing one several FPS faster than the rest. BTW I use the Lee Crimp die |
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Quoted:
How many people crimp their .223? I just bought 1500 rounds of 62gr. FMJ without the cannelure. I know the cannelure's primary purpose is for high recoil and automatic weapons just like the crimp on the primer. Being used in an semi-auto AR, is it really necessary? I always crimp. When I work up a new load I use a light crimp using a Lee Factory Crimp die. When I get all components set up for the round to give a good group, Then I will work with crimp to lower the Standard deviation number. IMHO YES to crimping on AR-15 due to the bullet jump being large. Mike |
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I crimp for all Pistol, Autoloading Rifles, and Magnum Rifles (providing a cannelure is present). The first two are for bullet setback, and the third is to make sure all of that slow burning powder does it's job.
I personally have had two bullet setbacks in an AR...Both were Nosler Ballistic Tips as Loaded by Federal in their premium line about six years ago. These bullets were quickly thrown into various places on the in-law's Cattle Ranch, so, no, I do not have photographic evidence. I now crimp all bullets with a cannelure for autoloading weapons. Now....There are loads in my Magnum Rifles that I do not crimp for, and I have tested enough of those specific loads to make sure that everything is going according to plan. I also do not crimp anything in my varmint rifles. ...My $.02 as usual. |
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I have a load worked out now for a 55 grain HDY FMJ BT with cannalure using once fired LC brass.
Its my high volume plinker round. I have a nice ballistic curve 25-300m with the arch/flat in the center so not a high charged round. The OAL is a tad higher than the S&B ammo I have which is good but short of max height so fits in a mag nicely. Took me a while but got it to where it loads very fast with the crimp right on the groove. I have no plans to work on load outs for non-cannalure bullets for now. I have a crap load of these 55 grains which should keep me busy. On my better ballistic coefficient rounds, I'm controlling the neck ID tightly for good retention and consitent jump off pressure. Jump off pressure is something I'm working on, so I'm setting up a pull off tester which is simply a fish scale and Hart bullet puller type thing. Gives me a good idea of tension and will look at crimps, tapers, neck length, and neck ID. Probably use the Nosler 55 grain ballistic tip. Why? Well, I have a good amount of those too. What I learn though can help on my precision loading all calibers and bullets. Told this to another loader which kind of did the same thing, he set his up using very light powder charges moving up to achieve just enough to get the bullet to jump. Then using powder charge to monitor his case changes. I didn't think of that but it sounds interesting (assuming you don't mind pushing bullets out of barrels lol). Tj |
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