rossiscratch
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- Mar 25, 2009
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I have a competition seating die for .223 that does not have a roll crimp feature(or other type of crimp). Is it not correct that cartridges reloaded for an AR-15 should have some sort of crimp?
Factory Crimp Die. Only Lee?
- Thread starter chagasrod
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I crimp all my plinking/rainy day .223 ammo for the same reason the military does. Not many folks crimp ammo loaded for accuracy in their AR's. I don't either, but I do like to give it just a tiny, itty bitty, almost isn't there, smideon of a taper crimp just to make sure the case mouth isn't hanging out there. Not really enough to count as a crimp.
Ret.CWO
Member
Crimp Die
Dillon sent one with the 30-06 set up with my Dillon 650 never checked to if they sell it separately
Dillon sent one with the 30-06 set up with my Dillon 650 never checked to if they sell it separately
rossiscratch said:
I know quite a few Service Rifle competitors that do crimp the necks on their reloads and they're very good shooters with scores consistently over 480. However, Sierra has some good information about crimping (or not) for Service Rifles which can be found HERE. I've copied the relevant section for convenience. They even mention the dreaded Lee FCD.
Neck Tension
When we stop to consider the vigorous (read, downright violent) chambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it.
There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition.
To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension. The first option, crimping, brings up some other issues that can be troublesome. In general, crimping degrades accuracy. Most match bullets are not cannelured (which also seriously damages accuracy potential), a requirement for correct application of most crimps. Still, there are taper crimp dies available from most of the major manufacturers. Lee offers their “Factory Crimp” die as an alternative, which seems to be one of the better options for those bullets without a cannelure. That having been said, crimping is still, at best, an occasionally necessary evil. Avoid it if at all possible.
The other—and in our opinion, better—option is increased neck tension. This, in turn, leaves us with two more options depending on what type of equipment you’re using. The object of either is simply a tighter grip on the bullet. Using conventional sizing dies, (i.e., those utilizing an expander ball) this is accomplished by reducing the diameter of the ball itself. This can be done by chucking the expander/decapping rod into a drill and turning it down slightly with fine emery cloth or a stone. The goal here is to decrease the diameter two or three thousandths (0.002" to 0.003") under bullet diameter. This is a trial and error process, and must be done slowly. The end result is an expander ball that opens the case neck up somewhat less than the as-issued item. This, in turn, increases the grip of the case neck on the seated bullet.
A better alternative to achieve the same effect is the use of a bushing die, such as those from Redding Reloading. This is by far the best solution, not just for Service Rifles, but for a broad range of reloading applications. The basis for this system is a fairly conventional sizing die, at least where the body and shoulder of the case is concerned. In the neck area, however, the die is fitted with a removable bushing. Available in .001" increments (as measured at the inside diameter of the bushing), they can be matched with a specific batch of brass to provide optimum neck tension. This tension can be increased or decreased by simply moving up or down in bushing size. The one drawback to this system, if it can be called a drawback, is the absolute necessity of sorting cases and loading them in batches. This, of course, is how virtually all loading should be done anyway.
snuffy
Member
Now this is where walkalong and I part company. I don't go along with that statement that the lee FCD "squishes" a rimless semi-auto round. It does iron out lumps and bumps from grossly oversized bullets, or excessively thick cases.
I know the theory that those of use that load oversized lead boolits will experience the FCD sizing the boolit a bit, and the supposition that the bullet will then be loose in the case. (It has to do with the lead staying squeezed smaller, but the brass springing back, creating a loose bullet).
Then there's what one guy over on castboolits.com said, that lee makes the fcd out of carbide sizer dies that got machined oversize by mistake. The inside diameters are all over the map, some are barely over the sizer die diameter, some are where they're supposed to be, .002 BIGGER than a sizer die. I dunno, could be! But I have more faith in lee than that!
All I know is the ones I have work as intended. The occasional boolit that escaped my culling, that's oversize, shows up as a harder to crimp than the others. If it's just barely oversized, I don't/won't notice it while running the dillon 650.
I don't doubt it. I am sure that is where the main problem stems from. I have less faith in Lee I guess. I know the carbide ring in the .45 FCD I have is way to small. Not sizer small though. The one I have in .40 rarely touches a round. I assume that is how it is supposed to work, and that's OK.
If someone is making rounds where a large percentage won't feed, and then they use the FCD and they do feed, something else is wrong. Sloppy seating, oversized bullets......something.
snuffy, and others, are not doing that. They use it to catch an occasional bad round. I have no problem with that.
My problem is with the folks who are making rounds where a large percentage won't feed, then they use the FCD and they do feed, and they think they fixed the problem. They haven't. Then they sing the praises of the FCD as a solution to feeding problems, which is shouldn't be. They need to solve the problem that causes so many rounds to need to be sized down, and not just size them down. That can cause other problems.
That's a good thing. It means your FCD dies are are not undersized, and you don't have any problems that need solving. (No rounds getting squished)
I use the FCD on my .45 reloads and have not had a problem. I set it up like the instructions say with about 1/2 to 3/4 turn past contact and the ammo looks and feels like factory ammo and works fine in my .45 1911. I dont see any reason to change and I like the post sizing deal.
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