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Posted: 5/14/2011 8:13:22 AM EDT
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I am loading unfired Lake City brass with a 55 gn Sierra Blitzking, 21.5 gns of Reoder 7, and Federal Gold Medal primers. I am attempting to copy a factory round produced by HSM that is extremely accurate in my Stag Model 6L. I trimmed the cases to 1.754. The OAL of my loads match the HSM loads. I did not crimp and the neck/mouth measures the same as the HSM round and they look identical. According to my measurements my rounds are exactly the same measurements as the HSM rounds.
When I fire this new round it fires and ejects every time but it fails to load the next round. Sometimes the bolt would be closed all the way with no round loaded and sometimes the next round would be caught at an angle with the tip of the round pointing up into the receiver. I think it is short stroking and wanted some advice on this. The 21.5 grains of Reloder 7 was a max load from the Sierra Manual. After shooting about 20 I decided to try shooting some the HSM rounds and they cycled fine. I also shot 10 PMC 55 gr rounds and they also cycled fine. On a positive not my loads did group well now I just need to get them to cycle? |
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RE-7 is used in the 55gr accuracy load listed here: http://accurateshooter.net/Downloads/sierra223ar.pdf I have never used it, however, so don't know if it would cause cycling issues. I still think that this is a result of not sizing the cases. |
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Thanks for the replies. I will run some of the new brass through a full length resize and give it a try.
My AR has a rifle length gas system and the Sierra Manual lists the test rifle as a Colt AR-15A2 HBAR. Would this rifle have a shorter gas system than mine and how would this affect pressure, cycling, and accuracy? Also, can someone suggest a good powder to use with this bullet/rifle combination? |
| I partially resize new brass but I'd bet your powder is just too fast for your rifle and 55 grain bullets. More people seem to have problems like yours with fast powders such as the 4198 powder with 55 grain bullets. You could carefully try increasing the powder charge. You're using different cases and primers than listed in the Sierra site. LC has more case capacity than Fed plus the 7 1/2 primer is different than yours. I suspect that your maximum load listed isn't maximum with your components and that you need to up charges to get reliable cycling with your loads and rifle. Carefully though watching for pressure signs. Check also where and how far the factory loads are ejecting spent brass compared to your loads which doesn't tell pressures but should show that your loads would cycle.. I'd try a slower powder than RE 7 and the short stroking will stop. |
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Have you ever gotten something stuck in your head that you just cant get out? For some unknown reason this thread has stuck. After further review, I have a couple of comments: 1: I was wrong when I said that failing to resize was a cause of the OP's problem. I will however stand by my conviction that I always full length resize the brass for my AR loads, even the new brass. 2: I agree that the powder in question is just a hair too fast. The OP's RE7 load would probably cycle my carbine just fine. It is however, on the ragged edge for his rifle length gas system. Something on the order of RE10x, H335, or TAC would be much better powder choices. GTO688 |
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Thanks again for the replies. After doing more internet research I agree with you about Reloder 7 being to slow for my rifle. This is the first time I have ever reloaded so I just went with the accurate load of 21.5 listed in the Sierra Manual. I did find an article where the shooter loaded 22.5 with a similar rifle as mine. Here is a link to this article...
Handloading the .223 Remington For the AR-15 |
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Quoted:
Thanks again for the replies. After doing more internet research I agree with you about Reloder 7 being to slow for my rifle. This is the first time I have ever reloaded so I just went with the accurate load of 21.5 listed in the Sierra Manual. I did find an article where the shooter loaded 22.5 with a similar rifle as mine. Here is a link to this article... Handloading the .223 Remington For the AR-15 Anytime I see a load that uses a very small charge of gunpowder with respect to the case capacity I am skeptical about it efficacy (there's a new $10 word for the forum!). Here are the reasons - the gunpowder is too fast for the case and bullet combination and can generate very high pressures without producing particularly high speeds, and the gunpowder lays in the side of the case, maybe causing erratic speeds and pressures and poor accuracy. Choosing a gunpowder that shows a small charge weight in order to save money is generally poor economy, and although it works and makes the bullet go, I consider these loads to be for those times when I need ammo and nothing else is available. One thing I do when I start loading a new cartridge or gunpowder is fill the case with gunpowder then weigh that powder to find out just how much the case will hold. Then I can judge how well published charges are going to fill the case. Short extruded powders should be compared to short extruded powders, and ball powders to ball powders for this to make any sense. |
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That depends on the number of loaded cartridges and whether you have plenty of brass and primers.
If it's just a handful of loaded cartridges, I would shoot them and suffer the function. If you have a bolt rifle or Contender, you could allocate the cartridges to that gun until they're shot up (good excuse for a new rifle, too), or you could also set them aside to use in your AR for hunting or even plinking. Disassembling more than about 50 loaded cartridges with a kinetic puller loses its charm quickly, and I can't say I think much of collet type pullers either, but they're definitely preferable for a long string of work. Reloading with more Reloder 7 is a bad plan. If you're going to do that, get some 40 or 45 grain bullets. |
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Quoted:
I only have 30 rounds loaded with the RX7 so pulling them wouldn't take too long. Lyman lists Varget as their most accurate load so I may go with that. I have read a lot of great reviews on H335 as well so its a tough decision. Note that............ When pulling bullets with a puller or a kinetic hammer style of puller........you might/probably will stretch the cases. Thus..........I'd remove the decapping pin (not to waste the primer) and just use the expander ball to keep the neck round (if your dies allows for it) and F/L resize those cases before resuse. Course......I'd also use a test gauge to check. Don't just use a caliper to measure and call it GTG (we're talking in the thousands of an inch.........trying to measure to the datum line and where exactly that'll be).........well, forgetaboutit, just use a proper test gauge. Aloha, Mark PS..............just because a book says a particular load is accurate.........well, it doesn't mean that it'll always be accurate (or the most accurate) in YOUR rifle (even when the test rifle is alike). |
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Thanks for the info. I loaded a few more rounds up with an additional grain(22.5) of Reloder 7 and these also would not cycle. I tested them by putting only one in the magazine and firing it. It did not have enough blow back to lock the bolt back so it was definitely short stroking.
I pulled the remaining bullets and resized the mouths as you said. I decided to go with Varget. I loaded 10 rounds each of 25, 25.5, 26, 26.5, 27, and 27.5. All rounds cycled and none had any signs of high pressure. The 25.5 and 26 grain were the most accurate. I decided to split the difference and load some at 25.7. I shot three 5 shot groups at 100 yards and they measured 0.524, 0.601, and 0.612 inches center to center. I also loaded some Hornady Match 75 BTHP and tested a few powder charges. I came up with 23.5 grains as my most accurate. My best 5 shot group at 100 yards was 0.38 inches. Prior to cleaninng my AR it was denting in the case mouths on ejection but after a good cleaning and running the proper load though her she leaves the brass undented. Thanks again for everyones help. |
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Quoted: Not sure how you're dispensing powder, but if you're throwing it I'd use H335. One of the best metering powders I've ever tried. Varget, not so much. I wish someone local would stock some TAC. I'd like to try it. I just test fired some TAC loads yesterday. Shot a 5-round max load of 26.3 gns with 55 fmjbt (bulk Midway is all I know) with a cannelure and I did not crimp. Using my 16" carbine with a 2 moa Aimpoint, I got an 1 1/2 group at 100 yds. The chrony said average was 2980. Kind of amazed me since the dot covers more than the group. So I like TAC so far. |
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