This is a discussion on Thoughts on Sadlak grooved piston... within the The M14 forums, part of the M14 M1A Forum category; I was wondering how many of you have a Sadlak NM grooved piston in their rifle? I have one but haven't had a lot of ...
I was wondering how many of you have a Sadlak NM grooved piston in their rifle? I have one but haven't had a lot of rounds through it yet. I shot some Port through it with a standard piston and the rounds ejected at 1:00, and with the grooved piston, it functioned reliably with the light 147gr bullets, but ejection was now at 3:00. The groove does bleed off some pressure, so you get a bit more gentle push on the gas system. My thoughts are, could this slower push extend case life by an extra reloading or two? The M14 action does open up quite fast, before the brass has a chance to shrink back down in size, so as the bolt turns to unlock, it twists the case in the chamber, and weakens the brass just above the head.
The slower push on the gas system might also reduce bolt recoil velocities, and thus reducing impact of moving parts, hopefully extending their service life. Just my thoughts, and I'd like your thoughts or personal experience too.
I know the groove was designed to be used for heavy bullets fired at near maximum loading, and it supposed to reduce bolt velocities. Over on Jouster's, I believe it was Gus Fisher who stated he saw many M14 receivers "pounded into useless junk from shooting heavy bullets at near maximum load." The bolt does impact the back of the receiver, and increased bolt velocities increase the impact force. This was back in the 1970's when the military had an endless supply of M14 parts, so it wasn't a big concern back then.
I use a G.I. piston and an adjustable gas plug from
Creedmoor Sports and their description pretty much sums up what I have found...
"Allows the shooter to manually adjust the speed at which the gas systems functions. By reducing the op-rod speed you:
-Reduce the wear on the bolt lugs
-Reduce the pounding on the receiver while shooting heavier bullets or hot loads
-For rifles that are glass bedded, it reduces the wear on the glass bedding increasing the number of rounds between skim glassing."
In experimenting I have found that I can easily adjust from "non-operational" cycling to closing the port and getting the full power cycling. I ended up adjusting it to one turn just past the point power-wise where it will not function. I get 100% reliability with a lot less "slamming." of the op rod.
Others who have shot the gun have noticed that there is something different about it but can't put their finger on it.
One interesting note is that you can adjust the group size to a degree with the amount of gas being used to cycle the action. And the instructions that come with the adjustable gas plug tell you this.
Old Sarge, if you have any questions about the use, or intended use, of any of the Sadlak products - just pick up the phone and call them. You will be treated to a real life lesson in what customer service and customer relations should be. Anyone you talk to there will know their product and can help you out. They are a pleasure to deal with for sure.
FWIW, the cases should land close to the 3 o clock position. If you are getting good accuracy and no issues with short stroking or any function problems, it sounds like your shooter likes the piston. There was an old thread about USMC armorers at Quantico swapping out pistons until one shot significantly smaller groups in that rifle. The tolerances of the piston & cylinder seemed to not make a difference. Just some pistons worked better in a particular rifle. Nice if you have a bushel basket of pistons to try, but still goes to show that if you have a set up that shoots well, don't mess with it. You getting good accuracy from this piston? If yes and no malfunctions, I would shoot and be happy. Also, copy what Easy said.
Ill tell you what Roland Beaver, USMC Match Armorer, retired, said:
I had 4 grooved Sadlak pistons bought, thinking they must be the cadillac, for my 4 LRB builds. I asked Roland after I had them, what he thought of those grooved pistons. He said he would rather have the plain ones. Mike Sadlak offered to take them back or exchange them whichever I wanted. He would "prefer" they werent heavily used.
I said, " Mike, Im not that low to even ask you to take back used parts"
So thats all I know. Nobody has more experience than Roland Beaver.
We tried grooved pistons for a couple of years when I was shooting for the National Guard. I didn't really find any significant difference or improvement with them. We felt the biggest advantage was between your ears. There was something comforting in hearing the piston slide back and forth when the rifle was tilted. We always knew the piston wasn't sticking. You don't get that so much with a non-grooved piston. As far as shooting heavier bullets, we never shot anything heavier than the M118 and shot more M852 than anything. I used to shoot some 180 grain Sierra's for long range and even they didn't seem too heavy for the M14. I don't recommend anything heavier though.
I had heard/read that the military match teams abandoned use of the piston with the groove cut. Inconsistency of shot groupings or something
I put a sadlak in my brandy-new LRB with the Criterion chrome lined medium weight barrel...300 rounds later I have gotten better groups with a GI Barrel @100 yards.
Don't know if the barrel is just "smoothing in" or what,, but I retired the sadlak for now and pulled a new USGI piston out of the wrapper and put it in the rifle...we'll see if anything tightens up next trip to the range...I'll be back