IPSC_GUY
06-15-09, 11:02
I installed a Bushmaster retrofit kit on my carbine a few months ago. The barrel is a Del-ton (read Wilson) 16 inch chrome lined 1 in 7, shortened to 14.5 with a permed YHM5C-1. It had roughly 500 rounds through it when I decided to try a piston system.
Since I have a Vltor VST gas block that I REALLY like and that I want to keep, I went with the Bushmaster / Aries system. I know the consensus is that the clamp style gas block is inferior to taper pins BUT so far the Vltor gas block has not moved one bit. I put witness marks into it and the screws and ZERO migration has occurred. All of the worry about the pounding of the piston back and forth also has not translated into any movement. I may pin it just to make Quadruply sure but for now I am in "Wait and see" mode.
ANYWAY, I just got done shooting the MGM Ironman and the this brought the round count on the conversion to just over 2000 rounds.
Some thoughts so far.
In the 2000 rounds fired, which has been a mix of Wolf 75 grain, Privi 75 grain and some PMC bronze, I have had exactly three failures.
1. Double feed from a Beta C that hasn't been graphited since I got it. I will choke that one to the mag.
2. Stuck Case of Wolf 75 grain. This was after firing 500 rounds of the stuff with out scrubbing the chamber. I am going to say that was my fault for not swabbing the chamber sooner when shooting Wolf for practice ammo.
3. Double feed from a brand new GI OKO magazine that had never been run before.
All three failures I think I can safely say were not the fault of the piston system.
There is a bit more felt recoil than the DI system, not much but it is noticeable.
My accuracy did open up a hair from .75 inches to .85 inches for 5 shots at 100 yards with 75 grain match Privi Partisan. this was the average over 5 strings of 5 rounds.
The upper and bolt stay much cleaner and I REALLY dig that fact as I have spent MANY years scrubbing Bolts and Bolt carriers. More on that later.
For the Match I ran 69 grain match Privi (I have more of it than the 75 grain) and it will hold .95 MOA out of this barrel. The upper ran fine all through the match and I was pleased as punch to have made first attempt hits on Steel IPSC targets out to 400 meters on stage 3 from the tower and from the ground.
Back to these things running clean, one of the great things about a Piston system is clean up and this is where the cost of the system pays off IMHO. At the end of the day when it came time to clean three guns and I was exhausted from crawling out of bed at 04:45, shooting all day and not getting back to the hotel till 20:30. The ability to clean the bolt with a couple of Q tips, then run a chamber brush in the chamber followed by a little felt scrubby for the extension, finished up by a couple of pulls of a bore snake, was worth every penny the system cost. I like my upper and bolt to be clean and this is Easy, Peasy ! ! ! No bolt tail scraping, no fighting with carbon in the carrier. Yes I have the tools and the know how to get my system clean but after 20 years of scraping crud it has become something I dread.
All in all my confidence in the whole set up is growing. I think that Bushmaster, in adding the barrel clamp and the bolt changes have strengthened the system a great deal.
Now just have to wait for one of Seth's buffers and life will be grand. Stay tuned for the 3000 round report.
IPSC_GUY
SIERRA II ALPHA
Since I have a Vltor VST gas block that I REALLY like and that I want to keep, I went with the Bushmaster / Aries system. I know the consensus is that the clamp style gas block is inferior to taper pins BUT so far the Vltor gas block has not moved one bit. I put witness marks into it and the screws and ZERO migration has occurred. All of the worry about the pounding of the piston back and forth also has not translated into any movement. I may pin it just to make Quadruply sure but for now I am in "Wait and see" mode.
ANYWAY, I just got done shooting the MGM Ironman and the this brought the round count on the conversion to just over 2000 rounds.
Some thoughts so far.
In the 2000 rounds fired, which has been a mix of Wolf 75 grain, Privi 75 grain and some PMC bronze, I have had exactly three failures.
1. Double feed from a Beta C that hasn't been graphited since I got it. I will choke that one to the mag.
2. Stuck Case of Wolf 75 grain. This was after firing 500 rounds of the stuff with out scrubbing the chamber. I am going to say that was my fault for not swabbing the chamber sooner when shooting Wolf for practice ammo.
3. Double feed from a brand new GI OKO magazine that had never been run before.
All three failures I think I can safely say were not the fault of the piston system.
There is a bit more felt recoil than the DI system, not much but it is noticeable.
My accuracy did open up a hair from .75 inches to .85 inches for 5 shots at 100 yards with 75 grain match Privi Partisan. this was the average over 5 strings of 5 rounds.
The upper and bolt stay much cleaner and I REALLY dig that fact as I have spent MANY years scrubbing Bolts and Bolt carriers. More on that later.
For the Match I ran 69 grain match Privi (I have more of it than the 75 grain) and it will hold .95 MOA out of this barrel. The upper ran fine all through the match and I was pleased as punch to have made first attempt hits on Steel IPSC targets out to 400 meters on stage 3 from the tower and from the ground.
Back to these things running clean, one of the great things about a Piston system is clean up and this is where the cost of the system pays off IMHO. At the end of the day when it came time to clean three guns and I was exhausted from crawling out of bed at 04:45, shooting all day and not getting back to the hotel till 20:30. The ability to clean the bolt with a couple of Q tips, then run a chamber brush in the chamber followed by a little felt scrubby for the extension, finished up by a couple of pulls of a bore snake, was worth every penny the system cost. I like my upper and bolt to be clean and this is Easy, Peasy ! ! ! No bolt tail scraping, no fighting with carbon in the carrier. Yes I have the tools and the know how to get my system clean but after 20 years of scraping crud it has become something I dread.
All in all my confidence in the whole set up is growing. I think that Bushmaster, in adding the barrel clamp and the bolt changes have strengthened the system a great deal.
Now just have to wait for one of Seth's buffers and life will be grand. Stay tuned for the 3000 round report.
IPSC_GUY
SIERRA II ALPHA