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Posted: 8/23/2009 7:32:34 AM EDT
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Alright, I have mentioned this before but...
Local gunshops, two in the area, say always taper crimp any auto loading cartridges because the feed ramp can cause the bullet to force back in the case on the feed. However, people here at ARF have said its not needed for the AR-15 or M-4. Also, most factory ammo seems to have a very modest taper crimp if any at all. Is it needed or not? Thanks |
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Might just be that they were talking pistol ammo. Not rifle ammo.
______________________________ But, even if they were talking pistol OR rifle...........the main idea is not to have ANY bullet telescope back into it's case. So, how you do THAT, is up to YOU. You could........crimp it, taper crimp it, or use only neck tension. Using "only neck tension" with pistol ammo is...........IMHO, risky. ______________________________ Getting back to rifle ammo...........note what SPEER says........... 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. My red and blue was added. The blue is info for any future "jawing" your buddies at the store may want to engage in. Aloha, Mark |
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Alright, I have mentioned this before but... Local gunshops, two in the area, say always taper crimp any auto loading cartridges because the feed ramp can cause the bullet to force back in the case on the feed. However, people here at ARF have said its not needed for the AR-15 or M-4. Also, most factory ammo seems to have a very modest taper crimp if any at all. Is it needed or not? Thanks First thing to ask them is whether they reload ammunition. If the answer is "yes", then ask whether they've tried loading both ways, or if they simply follow the recommendations in the load manuals. |
| I don't normally crimp for a bolt gun. I ALWAYS crimp for a semi-auto (Lee factory crimp die). And yes, i have crimped bullets that do not have a canellure. If you were to pull the bullets on the 69 or 75 grain PPU match ammo, you will find a bullet with no canellure with a fairly heavy collet crimp on it. The Lee factory crimp die uses a collet to crimp, it is almost a roll crimp. |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. Sir, WADR I don't believe you have offered any objective quality evidence supporting the use of a crimp with this cartridge. In answer to the OPs question, there is no generic one size fits all answer to the question of "to crimp or not to crimp". Most reloading manuals make comments regarding the presence of crimping grooves on the bullets as indicative of a need to crimp and lacking such grooves being indicative of crimping being unnecessary. My personal take depends on the type of cartridge in question. For straight wall revolver cartridges using bullets with crimping grooves I generally crimp the cartridge to the maximum the seating die will accomplish. For straight wall pistol cartridges for a semi auto pistol I use enough taper crimp to ensure the bullet will not be forced into the cartridge case during feeding. I determine the necessary amount of crimp by manually cycling reloaded cartridges through the pistol with the firing pins removed. Lastly when reloading semi auto bottle neck rifle cartridges with bullets that do not have crimping grooves I rely solely on case neck tension to ensure the bullet is not pushed into the case when feeding into the chamber. I accomplish this purpose by 1. ensuring all resized cases have the same inside diameter by using a case neck expander mandrel subsequent to resizing and that the case neck ID is .002"-.003" less than bullet OD. and 2. by ensuring the finished case length after trimming are all the same. HTH, 7zero1. |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. Same here. Edited to add: I even used a LFCD on Sierra 69gr MKs when I shot High Power, they still shot great. I hope Sierra doesn't sue me for doing that. |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. Sir, WADR I don't believe you have offered any objective quality evidence supporting the use of a crimp with this cartridge. In answer to the OPs question, there is no generic one size fits all answer to the question of "to crimp or not to crimp". Most reloading manuals make comments regarding the presence of crimping grooves on the bullets as indicative of a need to crimp and lacking such grooves being indicative of crimping being unnecessary. My personal take depends on the type of cartridge in question. For straight wall revolver cartridges using bullets with crimping grooves I generally crimp the cartridge to the maximum the seating die will accomplish. For straight wall pistol cartridges for a semi auto pistol I use enough taper crimp to ensure the bullet will not be forced into the cartridge case during feeding. I determine the necessary amount of crimp by manually cycling reloaded cartridges through the pistol with the firing pins removed. Lastly when reloading semi auto bottle neck rifle cartridges with bullets that do not have crimping grooves I rely solely on case neck tension to ensure the bullet is not pushed into the case when feeding into the chamber. I accomplish this purpose by 1. ensuring all resized cases have the same inside diameter by using a case neck expander mandrel subsequent to resizing and that the case neck ID is .002"-.003" less than bullet OD. and 2. by ensuring the finished case length after trimming are all the same. HTH, 7zero1. I believe that most loaders that crimp 223 do so because, as Hoppy said, it makes them feel better. The danger is that incorrectly taper crimping can actually loosen the bullet in the neck. As 7zero1 says the correct way to achieve neck tension for bottle neck cartridges is with correct neck sizing. I have found that if I use a factory supplied neck expanding mandrel the diameter is too large and only provides (for my loading) 1 mil or less neck tension and I prefer at least 2 to 3 mils. To use a mandrel I found it necessary to machine them so that they are 3.5 mils smaller than bullet diameter. Brass spring back then creates 3 mils neck tension. |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. Same here. Edited to add: I even used a LFCD on Sierra 69gr MKs when I shot High Power, they still shot great. I hope Sierra doesn't sue me for doing that. That's pretty much what I'm getting ready to load and will be using the LFCD. How much did you crimp? I know it's subjective but just a lite touch with the die or something more substantial? Thanks in advance. |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. Same here. Edited to add: I even used a LFCD on Sierra 69gr MKs when I shot High Power, they still shot great. I hope Sierra doesn't sue me for doing that. That's pretty much what I'm getting ready to load and will be using the LFCD. How much did you crimp? I know it's subjective but just a lite touch with the die or something more substantial? Thanks in advance. I only give the die a half turn after it contacts the shell plate. |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. Same here. Edited to add: I even used a LFCD on Sierra 69gr MKs when I shot High Power, they still shot great. I hope Sierra doesn't sue me for doing that. That's pretty much what I'm getting ready to load and will be using the LFCD. How much did you crimp? I know it's subjective but just a lite touch with the die or something more substantial? Thanks in advance. I only give the die a half turn after it contacts the shell plate. Got it. Thanks for the info as it'll give me a good starting point. |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. Same here. Edited to add: I even used a LFCD on Sierra 69gr MKs when I shot High Power, they still shot great. I hope Sierra doesn't sue me for doing that. That's pretty much what I'm getting ready to load and will be using the LFCD. How much did you crimp? I know it's subjective but just a lite touch with the die or something more substantial? Thanks in advance. I only give the die a half turn after it contacts the shell plate. Got it. Thanks for the info as it'll give me a good starting point. The half turn is spec for crimping to a channelur (sp), for the 69gr MKs, which don't have one, I did exactly between a quarter and a half turn after contact (135 degrees). |
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I crimp my 223 loads for my AR because it makes me feel better. I shot the same round crimped and uncrimped and found no real difference in accuracy or reliability. My experience as well. I crimp all my rounds, even match loads, using one of those Lee factory crimp dies. It gives a consistent tension that, in theory, will result in consistent initial burning before the bullet pops free. Less theoretical, a crimp makes it harder for the bullet to be jarred forward or pushed back for whatever reason. Rarely happens, but if it does, that will have a noticeable affect. I give it what I consider a medium crimp. I'm not a fan of roll crimping. That can be tricky to set up. And if there's any inconsistency in your case length, that will propagate to the tension of your roll crimps as well. Which means it will take different pressures in the case to release the bullet. Trying both costs very little, so do that. |
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crimping is a waste, unless you plan on storing it for a long time, or expose it to the elements
ever see any match ammo crimped, even military match? 
and if you do have a need to crimp, make sure you seal your primers with nail polish or some thing, it seems kinda useless if not jmo |
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I am new to reloading myself (technically haven’t even started yet) but I can tell you this much… there is no need to worry about a round catching the “feedramp” on an AR type weapon. You have to remember that most AR’s don’t even have feedramps. Only those AR types with “M4 Cuts” or “M4 ramps” have feedramps and those were developed for weapons in the field that were using weak magazines. In a properly functioning AR with good mags, a round will never touch anything from the mag to the chamber. You can test this yourself by watching through the ejection port as you slowly load (ride the charging handle) a round. If your weapon is in spec and your mags are good you should see the round being stripped and loaded straight into the chamber without ever hitting the barrel extension (or M4 ramps if you have them).
Local gunshops, two in the area, say always taper crimp any auto loading cartridges because the feed ramp can cause the bullet to force back in the case on the feed. However, people here at ARF have said its not needed for the AR-15 or M-4. Also, most factory ammo seems to have a very modest taper crimp if any at all. Is it needed or not? Thanks Now all that said, when using rounds with cannelure, I do plan to apply a light roll crimp as it can help prevent setback and it just seems like the right thing to do. Better safe then sorry and all that. 
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