NRA High Power

[Panther Lenny]

There has to be others like me, shooting NRA High Power using an AR 10 Platform (DPMS LR 308 Classic) Service Rifle. Finally a website dedicated to the gun! Thought I would start this topic to see if there are others that have been working with this platform and discuss what has and has not worked.

For my part- off the shelf, the gun has not been as accurate as needed to shoot consistant at 300 and 600 yards. (Yea I know, the gun doesn't change the shooter....). So this winter I am sending the gun off to Kreiger to have a new barrel fit and am going to switch out triggers.

So why not a .223?? Frankly I like the ballistics of the 308 and the tradition of the .30 round. When we are talking about loading Match King ammo, the 168 or 175 Gr. bullets there isn't that much difference when 80 gr bullets are used.

So hopefully others are out there! Hope to hear from you! <thumbsup>

[edgecrusher]

haven't shot in competition but the barrel is a start. the trigger is even better. free float hand guard. now we are getting started. oh, and not to be a stickler but there is only one ar-10, and that's an armalite. so, now that that's covered, are you allowed to run optics? what are you using? bipods? oh, yeah, welcome to the forum, hope you brought some play money  <thumbsup>

[Panther Lenny]

In NRA high power the only sights allowed are A2 iron sights, no scopes. Shooting os done from prone to standing with military type straps allowed in prone and kneeling postions. You can also use a shooting coat. So you might look at this as old fashioned marksmanship. . . Go to you tube and search camp perry and you will find it there.

Thanks for the welcome!

[Rhino55]

Lenny

I went distingished with a M-1A and yes the 30 cal rules!  I shot my M-1A barrel out and was given a 1-10 twist to replace it with.  After one season with it, I replaced it with a 1-12 Keriger match contour. Little on the heavy side but I was steady in the wind.  I found the 168 and 175s both loved the 1-12 twist.  Buddy of mine turned me on to them but he owns a LARGE ammo factory in SD.  I'm using Keriger 1-12 5R blanks for my first AR-10 builds.  If I don't like them I'll go to Rock Creek Barrels.  I've used thier barrels on some AR-15 builds and bolt gun builds.  Us high power shooter are getting far and few between.  Hold and X and pray for a 10.

Rhino55

[N Jensen]

I have been using the DPMS Ar 10 in High Power as a match rifle for 6 years now. Shot some of my best scores with an AR 10. 498, 792 - both were shot at the creedmoor cup matches one in a team match and the 792 to win the match rifle class and placed 3rd over all. Right now my 6.5 Creedmoor gun is my best shooting of the 3.

[Jgun]

Rhino, I went with the Krieger heavy contour in 1/10 ROT for my M1A build. I was led to believe that the 168-175's liked the faster twist. Can you tell me what your experience was with the 1/10 that caused you to go to the 1/12 after one year? I'm also under the impression that Krieger doesn't offer 5R rifling on any of their gas gun barrels, am I correct in understanding that you are purchasing their 5R blanks and installing the barrel extensions, and drilling the gas ports yourself?

[N Jensen]

I've used M1A in HP for many years and used 1-12, 1-11, 1-10 barrel twist before going to the match rifle and then AR 10 match rifle. My experience is that I couldn't tell the difference. As long as the rifle was built correctly and a good bedding job they all shot the same. That goes the same for no lug, single lug, and double lug as well.  The rule of thumb in the hay day of M-14/M1A at Camp Perry was if one was going to shoot 168 at all yard lines was to use the 1-12 as it was closer to what the twist rate was for 300 meter rifles and the 168 MK. But if one wanted to shoot the 180 and later on 175 or heavier bullets go with the 1-10 for 600 yds and beyond. The 1-11 was for the guys who couldn't make up their minds. Also, even a Palma rifle with a 1-13 twist barrel will shoot 175g MK just fine. I also like to add that with the new version of the 155g Palma bullet at 2800 FPS (which is very due able in a M1A) with a .500 BC is another option that can clean the target at 600 yds very easily. Just food for thought.

P.S A good bedding job for a M1A isn't that hard to do, if you want I could give you a basic step by step procedure if you like. I know this isn't a M1A form but I couldn't help myself. Sorry.

[unforgiven]

Just caught this thread lots of good info thanks guys. <thumbsup>

[Jgun]

N Jensen,

I appreciate your offer on the bedding. To be honest with you, I didn't build this M1A with highpower competition in mind. I've not (yet) tried that. I have been shooting IPSC , and IPSC style, pistol, rifle and shotgun, for a couple of years now, and really enjoy shooting on the move. I actually joined a club where they run those type matches. I believe that they also run some highpower style matches, and may try them once it's finished. I actually decided to build the M1A because I was looking for a new challange, something other than an AR. I did not build it in a manner that would make it legal for service rifle competition, because I've built it on an LRB M25 receiver. I had in mind to see how accurate of an M14 type rifle I could build, and the first part I ordered was a JAE chassis type stock. I am still hoping to see that some time soon. I plan to complete the gun (maybe this week if work allows) and then I'm going to try it out as is before I consider bedding it. I was pretty surprised at how well the barreled action and the stock locked up when I installed the trigger. The heel is tight against the top of the stock, and there is clearance  around the gas cylinder (unitized) without any work from me. The only thing I needed to do, other than inletting the stock for the rear lug, was to relieve the sides of the stock where the heavy barrel op rod guide contacted it. I'm actually pretty impressed with the fit of it with just the minimal work I've done. This being a GI stock (with selector cutout) it's not as stiff up front as those heavy stocks. I'm not sure if this GI stock is going to show much improvement in accuracy from bedding, what are your thoughts? I thought that if I did bed it, I'd probably want to install the pillar for the rear lug, but I see that you say that you have not seen any accuracy improvement from lugged receivers so maybe it's not worth the trouble?

[N Jensen]

I have seen the JAE stocks but have no experience with them. If I'm correct Allen was an outstanding service rifle shooter on the Army Reserve team through out the 80's and into the 90's. He even won the Porter cup at Perry with a NM M-14 twice. He builds a very good NM M14 or M1A. i'm sure his stock would work very well and would have a great shooting gun. 

If you are temp installing your action into old light military rifle stock you may be disappointed in the accuracy but at least you will be shooting. Installing the gas system by most people are installed to tight, not center over the gas port on the barrel, and piston not in alignment with gas housing center over the gas port in the barrel. Lastly, gas plug to long which makes a short stroke on the op rod before unlocking the bolt. For maintenance, clean your gas system, use drill bits to clean the carbon out of the plug and the inside of the piston (the piston will require two different size drill bits to clean). The rear lug in the rack grade stock will not provide any benefit unless the lug is glass bedded. Original M-14 relied on just the receiver legs against the insert in the rifle stock. The trigger needs to lock up very tight, shim with bedding material or some shims. If it locks up tight from the get go, it would be good to go. You should place grease on the op rod guide and in the track on the side of the receiver. Also put some grease inside the receiver, the area on the bottom side of the receiver where the bolt rides in while the hammer is pushing up on the bolt when in the stock, lastly a little grease on the hammer as rides on the bottom of the bolt. Shooting a rifle dry doesn't help, but over time, all it does is wear parts out. lastly I always thought that the gold piston didn't make the rifle shoot better, it really sucked. Just use a standard piston. When tweaking your rifle to get the most out of it. Try a bunch of different pistons. The Marine Corps rifle team when testing new builds would swap out pistons to get the rifle to shoot less than a minute on a machine rest at 300 yds. If after ten pistons or so and no improvement the rifle was sent back to the main gun shop. I was never in the Marine Corps but shot at Quantico enough to learn their routine. Hope this helps if you have questions, I'm more than happy to help.

[Jgun]

Thanks for sharing your knowledge. As this is my first M1A build, and first M1A too for that matter, I know that I've got a lot to learn. I'm not expecting too much in the way of accuracy out of it mounted in the GI stock, but it will allow me to function test, and will provide a starting point. I have a question regarding the gas cylinder installation. I purchased the unitized gas cylinder, along with the op rod, trigger, and bolt from a guy that told me that he collected them in the 70's for a planned build that never happened. He claimed that the parts were NOS, and from the appearance and measurement of them I believe him. Anyway. The unitized gas cylinder, came with a GI pistom. and the plug. It appears as though it might have been adjusted as you describe, aside from the welding. Is there a easy way for me to double check that the plug is not too long, now that I have the barrelrd action assembled? Also, thinking like a machinist, I thought that the method that the gas cylinder is secured to the barrel left something to be desired. When you tighten the gas lock, it puts pressure on the front of the gas cylinder but the rear of the front band of the cylinder, has nothing behind it, so the pressure you put on it, is transfered to the lower portion of the gas cylinder housing, and through that to the back portion of the housing which rests against the shoulder of the barrel. I turned a small spacer that is .001" smaller than the space between the front and rear bands of the gas cylinder. by doing that, when I tightened the gas lock the pressure imparted on the front of the gas cylinder is transferred directly to the locating shoulder of the barrel in a linear fashion. Do you know if anyone has tried that? As far as overtightening the gas cylinder I don't think I've done that as the gas lock stopped at 5:30 just as you'd normally want. I'm hoping that the spacer may add some rigidity to the barrel in that area. As far as aligning the barrel port with the gas cylinder port, I used a stepped pin and found that it lined up with no shims behind the back of the gas cylinder. Are there any other things that you might suggest for me to C/O on my assembly?

[Jgun]

N Jensen,

After my last long winded post, I remembered something else I wanted to ask. Maybe you might know somthing about this. What I found when I installed the NOS H&R trigger was that the trigger pull was much better than I had anticipated. The pull weight is not as heavy as I was expecting, and the break is really crisp, but there is a LOT of take up with almost no resistance, before I feel the resistance and then the break. Is there anything that you know of that I can do to remove some of that long take up?

[N Jensen]

For a great trigger I would contact http://tlcgunworks.com/ and talk to Tom. He could tell you anything about m-1/M14 trigger work and could also build a very good M1A. As far as installing gas systems one needs to ensure the gas system doesn't move. The old way was shims, they can be bought from fulton armory. The shims come different thickness. Place the shims on the barrel and using the figure 8 drive the gas system into the shims to the shoulder of the barrel. Once done, the gas housing hole is now centered of the hole in the barrel. It might take all 3 shims or one, or a combo. Use a small drill bit you can tell if the house is centered. Once that is done the figure 8 may not come to 5:30 position. If it is at 3:00 you will need to thin the figure eight. Other words, use a flat file and file the one side of the figure 8 until it goes snug at 5:30 and then pulled tight to 6;00. if the figure 8 goes past 6:00 flip it over and try the other side. Another way to ensure the gas system doesn't move is red lock tight. But you need a propane torch the heat it up and to remove the housing again. If you had to thin the the figure 8, the gas plug will need to be shorten. Lastly, place a empty case into the chamber and close the bolt. With the gas piston in, slowly tighten the gas plug. Gas plug is tighten it should only push the op rod off the bolt roller by a 1/4 turn  (1/4 turn the plug should bottom out and with the op rob barely moving), a small gap between the roller and the rearward end of the op rod area. If it takes like 2 turns to bottom out the plug and pushing the op rod while doing this, the gas plug is to long. File it shorter as needed and try and keep it square as well. Using a small pencil make a mark on the piston through the vent hole in the housing. If everything is done correctly, that pencil mark should be in align with the hole in the piston, which should line up with all the other holes. In other words properly timed. You have to admire the 14 gas system. Once it receives pressure from the barrel it shuts off the pressure hole in the barrel as it starts to move. The area within the piston and gas plug ensures enough gas volume to function the rifle. Once fully stroke happens, it vents over board. When the piston shuts off gas, that short distance on the op rod travels before the roller goes into the caming action area. This short space allows the bullet to be further down the barrel and a higher FPS before the action unlocks. This is why one needs to check that the op rod is fully fwd as possible when the action is in battery. Some people thought/think the op rod should engage the roller in battery while others thought it was more important to ensure while in battery that the gas system was back to the exact same spot each time, to ensure parts are not moving. I prefer a small gap / 1/4 turn on the plug.

Food for thought, every gun smith has his ideas, one can nick pick this away. Just my 2 cents, if the gun is short stroking, its the gas system. If the gas system is installed to tight, IE snug at 3;30 and pulled to 6;00 it will bend the barrel. and no matter how low the rear sight is, the bullet impact will be 8 inchs or so high at 100 yds. I have seen this many times. But the barrel will go back to it's normal straightness once the gas system is installed correctly. 

Have fun.

[98Z5V]

Damn.  :o  If I decide to tweak an M1, I'm sending it to you.  I wouldn't care what the price was...  <thumbsup>

That's some good info... 

[N Jensen]

We shoot HP every weekend in Las Vegas except Thanksgiving and Christmas. On the 2nd Sunday of each month is Palma practice 800, 900, 1000yds. F-class is welcome  as well. So come and shoot and you can bring your M-1, more than happy to show you anything you want.

[unforgiven]

Is that M1 only brother Jensen? <dontknow>

[Jgun]

N Jensen,

First of all thanks again for sharing your obvious expertise in this platform with us. I know that this kind of knowledge takes years to aquire. I have purchased a couple of books to help me in the building of this rifle, but I'm finding that your information/guidance seems much more clearly stated than what I'm getting from them. I had not even considered the timing of the gas system until your post addressing it. My rifle is not finish chambered yet so I realize that my measurements are going to be off, but after reading your post I took a look at my rifle tonight.What I found was that the gas plug began to apply pressure and move the op rod 1 and 1/4" revolutions before it locks against the front of the gas cylinder housing. I also double checked the gas cylinder housings port alignment to the barrels gas  port and find that there is no mismatch, the barrels gas port is not obstructed in any way. I also found that when I tightened the gas plug one quarter turn after it contacts the oprod, and then marked the bottom as you advised, when I check the pistons port relationship to the housing port, they appear to be mislocated by about .025" with the piston needing to move rearward in order for them to start out in alignment. Now, here's my question. You discussed removing material from the back of the gas plug so that the piston doesn't start out either too far forward, or too far back so it would already be caming the bolt. I think I understand the concept, but I notice that my piston, that I have been told was given the NM treatment when the band was welded to the housing, appears as though material was removed from the back of the piston where it contacts the op rod. I'm thinking that if I were to remove .025" from the back of the piston, the pistons port would be in alignment with the barrels gas port, and then I could remove whatever other material was needed from the back of the gas plug in order to have the ports in alignment, with 1/4 turn of gas plug pressure against the op rod? Is material sometimes removed from the back of the gas piston to achieve the proper alignment and timing of the gas system? I have no intention of doing anything with the piston or plug until I have chambered the barrel and rechecked the measurements with a shell casing in the chamber to properly locate the bolt, but I'm just wondering if I'm on the right track here. As I understand you, I want the gas plug to be applying 1/4 turn of pressure on the op rod so as to unload the bolt, and the gas port in the gas piston to be in perfect alignment with the gas port in the cylinder housing, is that correct? Nor sure if I should be posting these long winded questions on the open forum or PMing them, I would be happy to handle it as you prefer, just wish to thank you for fielding these questions.

[N Jensen]

In the late 80's when I talked to one of the Marine armors he talked about ensuring the housing, gas port , and piston were all aligned while in battery. He would shorten the op rod and or piston. But one could only remove only so much on either part to accomplish the goal. After looking at my rifle, I decided to shorten the gas plug as it was a 6.00 part vs a 125.00 op rod. The piston is hard, and using a file, that was a long process. My idea of shorten the gas plug accomplished the same goal. Not being there with you and your parts it's hard to tell you which way to go. I have several shorten gas plugs in my kit, but one day one gas plug might work on another gun. Not a lot of people looking to glass bed and accurize M1A's any more. Until you have the chamber done and empty case and action in battery it would be hard to tell which way you should go. You understand the end goal, I'm sure you will be fine. If the gas piston was shorten, I would recommend getting a brand new one and start with new parts.

[N Jensen]

Shooting in Vegas. You can shoot anything you want except a 50 BMG in our Palma practice match or in the HP across the course. We normally shoot a 80 shot practice match on the other weekends. On the months were there is a 5th weekend, it's a 1000yd only rifle match. Again F-class is welcomed as well.