Re: Holy POI shift, Batman!!!!!!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RollingThunder51</div><div class="ubbcode-body">..
I actually think your can is just fine.
What you have are two seperate issues, one well discussed already. The Delta P device is really just an ok bridge. They go out of their way within their own literature to explain that the limitations to concentricity is based on the accuracy of the barrel work itself. In your case, I think you will find that your barrel will require a better crown.
Their own words: "inspect the existing muzzle threads and end face of the barrel to confirm thread concentricity and end face perpendicularity to the bore axis." and "special care has been given to maintaining bore alignment to the greatest possible degree given the geometry of the M14/M1A barrel."
On top of this you are triple adapting. barrel to yoke to QD. That is allot to ask. Possible, but it is the kind of work you should be confident was done bone solid.
Lastly, this rifle was never intended to be surpressed, just the opposite, the gas system was designed to handle any round within reasonably mil spec. As such, unlike other .308 gas guns, it is not even adjustable in its intitial configuration. I have written about this a number of times on these threads, THAT rifle needs to have its gas system tuned to insure not only accuracy but proper bolt operation. I have even seen this rifle be set up to be suppressed perfectly only to get completely out of whack accuracy wise with the shortening of the barrel. The reason was ALL gas system, the barrel shortening work was perfect.
The solution is four fold:
1. The can is design exclusively for the rifle and the internal can pressures "matched" as much as possible to the gas system from the get go. Your threading is either direct to barrel or quality QD. Sas is not designed as a M1A can, no problem, we move on.
2. A series of 3 gas spindles are produced with different passes allowing the right one to be selected for a particular can. Some suppresor companies that make a dedicated M1A can <span style="font-weight: bold">will not sell </span>the can unless they set up the rifle and swap in the right spindle. I could throw a couple of names out, but folks hate it when I do.
3. Adjustable gas plug. They work, I have them. These make up for the lack of adjustability within the initial design. Like, say an FN FAL, where the actual gas flow can be adjusted. But even in the FN FAL, when surpressed, the gas hole has to be welded shut and redrilled to a new spec. Adjustables are handy for your favorite match load...or tuning for a suppressor not specifically made for your rifle. Just enough pressure to properly cycle, no more slamming. Most folks haven't got a clue and simply won't be bothered, they are beating it out of their op rod. The fact that the person that owned your rifle prior to you drilled the shut off to ALLOW gsa, may mean he set your up for a suppressed rifle! In other words, he knew enough that when he shot suppressed he would turn his shut off OFF and it would allow the right amount of gas through for his can. Did you get the can from him too? If you did, well ask him if you should be shotting gas OFF.
Here you go:
http://www.midwayusa.com/viewProduct/?productNumber=699378
http://www.creedmoorsports.com/store/product.php?productid=16363
Their sheet:
http://schustermfg.com/pdf/adjustable_m1a_gas_system.pdf
One way ticket this...your setting up for suppressed, or you are setting up for non suppressed...only.
Notice the warning "can damage the rifle" right, improper gas loading can damage the rifle. Suppressors can damage that rifle too.
4. Shut it off. This is a valid option for some.
When you said that you bought the rifle used and the prior owner had work done, well my alarm goes off and so should yours. Find out exactly what work was done.
In the end, if your using optics and expect to shoot the rifle suppressed a majority of the time? Rethread the barrel properly or send the rifle in to somebody that knows what they are doing.
Good read for you on the gas system and its importance:
http://www.zediker.com/articles/m14_2.1.pdf
Good luck, please let us know what the solution was. That rifle will shoot great suppressed when properly set up. Just know it is still comparitively loud...unless you shut it off. </div></div>
Thanks for all your leg work RT... That was very helpful.
I'll probably just not run the can on this rifle. I really just threw it on there for shits and giggles since it had the Delta P adapter on it, shooting this rifle suppressed was more a passing fancy than an actual desire.
I will get a couple of those adjustable gas blocks though, they seem like a great thing to have regardless, and it sounds like my Scout needs one anyway.
Thanks again for all the help!
