AR Sponsor
Posted: 8/21/2011 7:19:52 AM EDT
|
I have a single rail DPMS gas block, and started to wounder if a gas block with better balance would improve accuracy in a rifle.
has anyone ever noticed a difference between a pinned, clamp on, or gas block attached with set screw or gas block shape in regards to accuracy and barrel harmonics. I would think a more symmetrical design could ring out a little tighter groups. right now i consistently shoot 1" 10 shot groups at 100yrds.prone position. So before I go wasting about 40$ on different gas blocks I'd like your input. I mostly target shoot, & hunt..sorry, I'm a bit of an accuracy nut.. Thank you |
|
Short answer, no!!!!
Long answer, with Buffer/carrier extra weight and even an adjustable gas tube, you held ring at a little better grouping on a match barrel (in the .01 range, but we are talking hand loaded match ammo already rigging about a much as you can rig out to begin with, then tuning the stroke to that ammo as well. |
|
Dano, thanks for your reply.
All I shoot are hand loads, lapua brass, sierra matchking bullets, rem br. primmer, hodgdon varget / or alliant reloder15 powder through a kreiger barrel.. I think I've seen the carrier/ buffer weight systems you refer to..i think it was from David Tubb...Although I haven't seen an adjustable gas tube. do you have any brand reference? |
|
If you are pushing +69gr ammo, then slowing the bolt down at unlock is ideal.
The slower burning powder you are using will create higher gas port pressure (think dwell time of the burn over faster powders, which makes the port pressure higher since the powder is burning longer in the barrel), which unlock the bolt faster than normal. So you can go at it one of any ways to slow the unlock back down, You can increase the mass of the B/C (Tubbs system), the Mass of the carrier (use tungsten steel discs, or just go with a new buffer made out of steel instead of aluminum), or go with an adjustable gas tube system to slow the unlock back down. As for price, Your looking around $50 for most of them and would advice the gas tube method if you do not have a machine shop since it will give you some fine tuning adjustment as is, where the others are really fixed units and would be playing luck of the draw. Myself since I do have a lathe, my method is a steel buffer since I can adjust the weight of it for the needed application/ammo being used. To add, take the time to read the below link to give you an idea of dwell port pressures, and remember that the power in the charts is for 55/62 ammo, with slower powders having higher port pressure (hence unlocking the bolt even faster) http://www.ar15.com/forums/t_3_66/266108_How_it_Works__The_AR_gas_operation_and_how_everything_works_in_harmony_.html |
|
OK..once again your the man w/ the plan..
well I knew these topics were here for a reason, I should have taken a look at them.. Randall's description of AR gas operation and how everything works in harmony. I am experiencing example #3 on ejection and yes i shoot only 69gr. matchking. every case has a slight gouge from the extractor..I thought it was from hot loads, and worked on a reduce powder charge, but accuracy suffered. so i went back to my favorite powder charge. so.. to slow things down a bit.. and allow the chamber pressure to drop before extraction, thus longer lock time. I've switched powders,increased, and decreased powder charges and my rifled did not like that..it lead to extraction, or feed problems, or just poor accuracy. seems to me were or the right track. .Another dumb question is about to be born..what is the difference between an, adjustable gas block, and an adjustable gas tube? is there better control with the gas tube?..I think i will take your suggestion and try out.. the weight system first if the results i seek are not met then I will try the gas tube or adjustable gas block. from what i read in online reviews the adjustable gas tube is a good idea but poorly made.. I will post results when ever i get around to changing out my parts I must add.. the one thing i enjoy most about the AR-15 is the ability to tweak things in hope of finding that sweet spot. I think it makes the rifle more fun..thank you for your time. |
AR Sponsor