Mini 14 gas bushing

[showmebob]

I posted this on another forum but received no replies. Can anyone here answer this?

I'm working up loads for my Mini 14 and had settled on 26.2 of ......being the most accurate. I installed an after market gas bushing and now the 26.2 shoot lousy with 26.5 being the best.
Can the gas bushing affect group sizes/charge amounts needed? I'm not concerned with point of aim to point of impact, just group sizes.

 

[desidog]

I'm no expert on semantics, but didn't you answer your own question?

 

[showmebob]

Maybe I should have explained a little further.
It would seem to me that the gas bushing should have no affect on powder charge requirements for accuracy and I've not heard of this happening before. So, does that mean that the act of changing the bushing is affecting things, screw torque, etc? Or, is it just something to do with conditions of the day or my shooting abilities? I'm not a rifle man, fairly new to rifles, more of a pistol person.
I am hoping a mini owner who has performed this modification will chime in with their results.

 

[courtgreene]

from the way you described it, it sounds like a larger bushing decreasing pressure. I can't imagine it making a huge difference, though, unless it's making the gun move because of the piston driven mess under the barrel going back and forth.

ETA: yes any of those other things (conditions, you, etc...) could have easily been a factor

 

[husker]

Its not the Bushing as much as it is the gun. If its an older pencil neck barrel. much will have to be done to get groups, that wont be laughed at. But it can be done.
#1 Cyro freeze the barrel
#2 Accu strut
#3 torque the 4 gasblock bolts down evenly with a torque wrench. I think mine are at 18lbs
#4 1911 recoil bushing on the both sides of the spring.

 

[rhinoh]

I swapped gas bushings to a smaller size in both my Mini 14 and 30.
Didn't notice in change in accuracy, but then the Mini's aren't noted for accuracy.
I swapped them because I got tired of looking for my brass 30 ft away..

 

[M1key]

Went with a smaller gas bushing to cut down on ejection and after re-torquing the gas block, noticed my rear sight zero is now shifted more to the center. It seems to shoot more accurately with my Win Q3131, too.

Ahhh, such is the fate of a Mini owner...voodoo, alchemy, and the black arts.

M

 

[tango2echo]

Mini gas bushings require a break-in period if you swapped the entire gas block. Don't clean the gun. Shoot the heck out if it for 200-300 rounds, then try the original load again. IME after they break in the orginal groups return if the gas block screws are the same torque prior to the swap.

t2e

 

[benEzra]

If it's a pre-580-series mini, you have to change the bushing at the correct phase of the moon, and may have to sacrifice a chicken if the phase is wrong. 580 and up are much less finicky.

(Former owner of a 188-series Ranch Rifle here...)

The mini is a very complicated dynamic system, and I suspect that changing one variable can move you either into or out of a "sweet spot" of vibration harmonics and amplitudes, sometimes unpredictably. You just have to experiment and run with what works.

 

[LoonWulf]

I noticed a change going from the stock bushing to the .045, and again going down to the .035, which is the smallest that will function my rifle reliably with the lightest loads i can get my hands on (PMC Bronze). The PMC and WW 5.56 shot about the same, or near enough for me not to be able to tell, but Groups went from about a 1.5" average to well over 2" with my 68grn hrndy and W748 load. Droping the powder charge to my .2 grns seemed to bring it back in line. Also BC-2 shot as well as 748 with the stock busshing, and i cant find a charge weight that will do under 2" with the .035 installed.

 

[showmebob]

Thanks to all for their thoughts! I'll keep testing and shooting (darn the bad luck). For the record the rifle is a new one and I installed a smaller bushing, same gas block, as the original one would throw brass 45 feet.
Now, off the find a sacrificial chicken for the full moon this friday...........