overgassed and accuracy

boltrunner

New member
i know i need an adj. gas block but how much if any dose being over gassed have with accuracy.i have a black hole pencil barrel 1-8 that will not group no matter what ammo i try.
 
Being over gassed is going to be harder on brass as the bolt is ripping the still expanded piece of brass out of the chamber milliseconds to early. You will see light rubbing on the case body in addition to scrapes and such on the bottom of cartridge.

This should not degrade accuracy. Pro shooters get better times with smooth cycling rifles. At the bench though... Unlikely.

You could look to see if your barrel nut, scope mounts and such are tight.
 
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The OG can give inconsistent harmonics as the bolt opens at various times and pressure on the cases varies from shot to shot a bit more than the undergassed. I hate ripping up cases and run more on the UG side for most of my guns. On an SD rig I run them OG because that's when it pays to have reliability. On the flip side too much OG can cause feeding issues and bolt bounce.

Many times the slowing down turns one from being temperamental to a nice manageable consistent loading.I learned my lesson on a 20 caliber rig and now when t comes to anything below 223 I will not even try to work up a load unless I can adjust the gas. It gives you many more choices in powder charges and types to play with IMHO.

I shoot virtually nos factory ammunition so I want the flexibility of the adjustable. Of course the caveat is that unless the port is big enough to flow the gas you don't have anything to work with. Most barrels come drilled to OG, some hugely overly large, but you do see some that are on that ragged edge that need a bit of drilling.

Greg
 
I have never seen an over-gassed barrel not shoot because the gas-port was simply too large.

You could have one of many problems: unsquare upper receiver. Do you get point-of-impact shifts when switching bullet-weights? Did you have to adjust your scope a significant amount to get it on paper? If yes, then I would get the receiver squared.

Assembly: is the barrel and gas-block free-floating? If you remove the BCG and roll the receiver over, can you move the gas-tube a little in both directions, in other words, does the gas-tube float?

The other would be simply a bad barrel.

If you want, send me the complete receiver. Remove the optics, but send everything else. I will disassembled it, square the receiver, borescope the chamber and bore, and reassemble it the way I do my full custom builds. If this fixes the problem, then you will be lucky, and all I would ask is that you pay return shipping. If this doesn’t fix the problem, I would be happy to fix you up with a Barrel that will shoot.
 
I have noticed groups tightening/shifting slightly when adjusting gas. I have also noted differences in gas blocks, switching from a cheap set screw to a clamp on. But none of these is going to turn one that's shotgunning groups into a shooter.

What kind of groups are you getting?
 
Originally Posted By: dtechI have never seen an over-gassed barrel not shoot because the gas-port was simply too large.

You could have one of many problems: unsquare upper receiver. Do you get point-of-impact shifts when switching bullet-weights? Did you have to adjust your scope a significant amount to get it on paper? If yes, then I would get the receiver squared.

Assembly: is the barrel and gas-block free-floating? If you remove the BCG and roll the receiver over, can you move the gas-tube a little in both directions, in other words, does the gas-tube float?
i may take you up on that
The other would be simply a bad barrel.

If you want, send me the complete receiver. Remove the optics, but send everything else. I will disassembled it, square the receiver, borescope the chamber and bore, and reassemble it the way I do my full custom builds. If this fixes the problem, then you will be lucky, and all I would ask is that you pay return shipping. If this doesn’t fix the problem, I would be happy to fix you up with a Barrel that will shoot. i may have to take you up on that
 
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Originally Posted By: boltrunnerdtech i may take you up on that

I hope you do! No one likes suffering with accuracy issues.
 
the scope is brand new first time mounted i just swapped it out with one i know is good. i'll take it to the range today or tomorrow and try it out.
 
Originally Posted By: tonyjabIs there a scope on it ! Something loose . base scews ring screws .bad scope

thats the usual place to start.

as suggested stick to the basics first - make sure you have a known good optic in there and all the bases and rings are true and torqued to 20 in/lbs

then start checking everything else.
 
Originally Posted By: dtechI have never seen an over-gassed barrel not shoot because the gas-port was simply too large.

You could have one of many problems: unsquare upper receiver. Do you get point-of-impact shifts when switching bullet-weights? Did you have to adjust your scope a significant amount to get it on paper? If yes, then I would get the receiver squared.

Assembly: is the barrel and gas-block free-floating? If you remove the BCG and roll the receiver over, can you move the gas-tube a little in both directions, in other words, does the gas-tube float?

The other would be simply a bad barrel.

If you want, send me the complete receiver. Remove the optics, but send everything else. I will disassembled it, square the receiver, borescope the chamber and bore, and reassemble it the way I do my full custom builds. If this fixes the problem, then you will be lucky, and all I would ask is that you pay return shipping. If this doesn’t fix the problem, I would be happy to fix you up with a Barrel that will shoot. WOW!!!! CANT BEAT AN OFFER LIKE THIS.
 
Originally Posted By: boltrunnerthat had been done. i swapped scopes and no difference couldn't get better than a 3 inch group at 50 yards.

IMO, over gassed or gas block rubbing on forend would not cause this bad of groups. Im thinking youve got a bad barrel. Heck i can throw rocks as accurate as that.
 
Originally Posted By: Catdog1Originally Posted By: dtechI have never seen an over-gassed barrel not shoot because the gas-port was simply too large.

You could have one of many problems: unsquare upper receiver. Do you get point-of-impact shifts when switching bullet-weights? Did you have to adjust your scope a significant amount to get it on paper? If yes, then I would get the receiver squared.

Assembly: is the barrel and gas-block free-floating? If you remove the BCG and roll the receiver over, can you move the gas-tube a little in both directions, in other words, does the gas-tube float?

The other would be simply a bad barrel.

If you want, send me the complete receiver. Remove the optics, but send everything else. I will disassembled it, square the receiver, borescope the chamber and bore, and reassemble it the way I do my full custom builds. If this fixes the problem, then you will be lucky, and all I would ask is that you pay return shipping. If this doesn’t fix the problem, I would be happy to fix you up with a Barrel that will shoot. WOW!!!! CANT BEAT AN OFFER LIKE THIS.

I agree
 
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