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I have noticed that my rifle has been throwing the brass at the 1o clock position and want to know if a extra power action spring will help to cure that. I was told it is a sign that it is overgassed.
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Why would you think this is over gassed? What terms of reference is there that this denotes the carrier velocity and acceleration is too high.
The case shape will interact differently with the extractor, ejector and shell deflector. Also the loading will change the ejection point. I would suggest that you examine the reciprocating mass first. -
Though various factors can come into play regarding ejection, the ejection pattern can indeed be an indicator for the gas system. With a 1:00 pattern, the best solution is likely an adjustable gas block.Originally posted by gunrestorer View Post
A stronger buffer spring and / or heavier bolt carrier should help, but these methods are treating the symptoms rather than the root cause. They work reasonably well for less severe cases in fine-tuning a system without an adjustable gas block.DrifterComment
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Thanks for the info, think I will try the adj. gas block.Comment
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Details of your set-up?
Barrel length?
Gas system length?
Gas port diameter?
Bolt Carrier type?
Buffer weight/type?
Extension tube length/type?
Recoil spring length?
Ammunition?Comment
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Barrel is 24in,gas sys. rifle, gas port .0935 bolt carrier standard buffer wt. standard ext.tube A-2 recoil springA-2. Ammo Hand loads CFE & 8208 2450-2600 on Vel. 120 gr. Nos. bt, 120gr. Sierra pro hunter. The barrel is a custom Broughton with .875 at gas block. If I go with adj. gas block I will have to open a .750 up to fit my barrel.Last edited by Guest; 09-27-2012, 01:00 PM.Comment
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First, do both 8208 and CFE loads eject to 1:00 ? Very different powders with burn rates from one extreme to the other in the Grendel spectrum. I can understand the CFE and other new slow-burning super powders causing issues on a system that runs fine on typical powders, but wouldn't think 8208 would be problematic.Originally posted by gunrestorer View Post
You definitely want an adjustable block if experimenting with such different powders, but if 8208 is making a 24" rifle barrel overgassed, something else might be a factor.
PRI makes an 875 adjustable block:
DrifterComment
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The 8208 throws the cases fine, I forgot to say that in the previous post. thanks for the info on th gas block I only have the Brownells cat. and did not see one in it.Comment
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+1 on the .875" PRI gas block, which uses a straight gas tube BTW. They won't advertise it on their site if they are out of tubes, but they do have them last time another forum member checked (last week), so I would give them a call. PRI makes quality stuff too.
Bwild97 has been having great success with CFE behind 100-130gr bullets, getting 3000fps with 100gr AMAX, and over 2600fps with 129gr SST & 130gr Norma Golden Target at mag-length COALs.
I would PM him to compare notes on what makes his 24" click.
When you say "Standard" for the bolt carrier, what do you mean? I lean to using an M16 carrier in all my AR's, but especially in the Grendel, as well as a heavier buffer to counteract the increased gas system pressure from heavier pills and larger powder volume than 5.56 generates.Comment
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I use the M16 carrier as well, have not tried the heavier buffer. do you use the heavier spring as well? As you can probably tell Iam realativly new to ARs. I have just gotten the bug about a year and a half ago. I have been restoring collectable rifles and shotguns for 35yrs. Didn't think I would ever own an AR until a buddy brought his out to my shop, as they say the rest is history. I now have one in 5.56 and the Grendel. I already have another lower and parts kit to build another for my 14yr old daughter. After she was shooting mine all I have heard is how much she wants one.Originally posted by LRRPF52 View PostComment
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I have a carbine with a carbine extension tube, which uses a shorter carbine recoil spring. I use a standard chrome silicon recoil spring with an ST-T2 buffer from Spike's.
A rifle buffer is just fine for the Grendel, since they weigh over 5 ounces.
The AR has become the new "Mauser action" as we go into the 21st Century, especially considering the availability of alternate calibers appropriate for hunting now. I have a new product line that I've been working on for months that is about to debut, and it will help with your projects. Do you have all the parts and tools for your daughter's build yet?Comment
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I have a new product line that I've been working on for months that is about to debut, and it will help with your projects. Do you have all the parts and tools for your daughter's build yet?[/QUOTE]
c'mon now, sneak peek?
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I have the tools, I still need an upper and all the parts for it as well as the stock,buffer and spring. I,am going to get a Black Hole barrel for it. I have an Aimpoint on the 5.56 she has been shooting so she wants one on her's as well. she likes the 5.56 but I want here to shoot the Grendel a bit before I build her one to see if she like it.Originally posted by LRRPF52 View PostComment
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Now this is actually going to sound strange, but for my competition rigs, I tune them to eject at 1:00 by trimming the ejector spring, they certainly aren't over gassed, and perform flawlessly. I fired a little over 14,000 rounds this season and had two failures, one due to a faulty primer, no anvil, and one due to no powder in the case. I've had no failures to eject or feed. So I can't help but think you are trying to solve a problem that isn't a problem.
BobComment
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Well, I certainly think the spring and buffer are more of a solution than masking the symptoms. I suggest you read this thread.
I think an adjustable gas block is a good fix, but a heavier buffer and spring can't hurt either.Comment
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