M14 Forum

Bamban

Since I had the luxury of having two primary double lugged M1As, when I re-barreled what used to be number 1, a rear lugged only, I asked Art, who pillar bedded it for me, to put all the things that he can think of that may increase the accuracy of the rifle. He has quite a few tricks under his sleeve that he put into the gun. Being the trigger monkey as my role in the project, there are some things he divulged, ones that are obvious, and then there are those that remained under his wings.

Before taking the project to Art, I sent the rifle to have a Krieger 10 twist barrel chambered with my own reamer, a modified Obermeyer Match reamer. Dave Sullivan from Westwind Rifles did the chambering. My intent all along was to use another large mouth FH done up by Memphis Machinist, along with my own reamer I asked Dave to cut the crown like a bench gun, an eleven degree crown and no chamfer. The large mouth FH does not engage the end of the muzzle, the castle nut bottoms out on the step on the outside of the barrel.

The project did not go without a hitch, in fact I was in constant email to Art Luppino for guidance. I struggled for awhile as to what combination will shrink the group. When I gave him the green light to put all the things together in this project I was assuming full responsibility as to the outcome. The whole rifle was experimental. We could have done it the conventional way and be done with, but that would be too boring. Exploration and quest for continuous improvement drives me.

Over the last three moths I changed a few things in the rifle. Tried the piston tests with different ones ranging from NOS GI piston, polished ones, and modified ones. Tried different FHs, different lug torque settings, different gas plug torque settings, all the different match loads I've used in different rifles. Replaced the spring. The only thing left to remove, replaced and test is the barrel and the gas cylinder. All the effort listed above did not yield any groups I was happy with.

One thing I did not bother to do anything about is the front band to stock mating. They are perfectly aligned to each other. The tell tale grease mark is even across. One the things done right the old way that does not need to be improved.

After a long bout with unacceptable accuracy I think I found the right combination. Today I took the rifle to the range as time filler as I rest from practice. I changed different things all at once so I can't tell if one item singularly improve the grouping or it is just the combination.

1. Large Mouth FH
2. Sadlak TiN piston, did not use this in the initial piston test. I've always used GI pistons for all my match prepped rifles. In fact I borrowed it from my Poly.
3. Torqued the rear lug at 65 instead of my usual 57 in any of my lugged guns.
4. Kept the gas plug toque at 150 inch pounds. As I mentioned I tried different settings before.
5. Removed the op rod mod to take it back to standard configuration.

I do intend to undo one or two of the items listed above, except for the large mouth FH, that guy is there to stay. I like the fact that I can keep the crown clean by accessing it from the end of the FH.

The group was shot with irons aided by a corrected lens provided by Art Neergaard at 200 yards on the SR target. Initially the grouping was great I was digging a big hole to the right of the X ring, I clicked to center. As we all experienced before, those holes touching are hard to duplicate. I stayed in the X ring though. The two at six were the product of accepting mediocre sight picture. The one at 4 I plainly jerked it there. I could have easily stopped after I shot the group on the right, which was 10 shots, but I wanted to shoot at least 22. The weather was near perfect for wind so I wanted to see what my NWZ is, the reason I clicked to center. Time was late in the afternoon as the wind died down a little and changed direction from 10 to now straight down at 12 o'clock.




Here are the other rifle spec.
1. McMillan stock, brown
2. Early 5 digit SAI, rear lugged
3. TRW bolt assembly.
4. Win op rod
5. SA trigger group with JMoore modified hammer MKII Mod 1 and Neergaard's adjustable trigger.
6. NM 2A rear sight with ball and detent to give 1/4 minute click. 1/2 minute elevation disc used. Dsic was given to me by Gus over a year ago. Hooded aperture is .0520
7. Machined down NM front sight for 10 minutes off the bottom 200 yard elevation.

levisdad

Nez, What was your load?

Dave P

That looks like a fine group - 200 yards prone? About 2 MOA?

Curious why you blacked out the 9-10-x letters? Does white lettering throw off your sight picture??

"Over the last three moths... did not yield any groups I was happy with. "

Boy howdy - been there done that, too many times. Used up a lot of barrel life looking for suitable performance. One memorable time, it took me weeks/months to find a cracked FH that was ruining accuracy.

Bamban

41.3 grains of IMR 4895
CCI 34
Once fired LC 87 from ball ammo, processed by Dick Whiting
COL 2.819
Nosler 155 molied

Bamban

Dave,

The group appears to be about 2 MOA. I do not believe in 3, or 5 shot groups except during load development. It was 200 yards, but from the bench, the ground was too wet. I normally test from the ground slung up, sometimes with the forward hand supported. The challenge for the 60 year old eyes is the ability to see a consistent sight picture.

At our high power range we do not have pits, all the target frames at 200 have the center cut out. The cutout is about the same as the SR black. During the match we hang white sheets about 8 feet behind the frames. We customarily black out the X, 10 and 9 so shots on the numbers are easily detected. If you notice the holes in the target I posted, the holes are clearly white. There was a white sheet hanging behind the target. Even in heavy mirage we can see holes with this arrangement. Now, you shoot in the white there is not much help there.

I've always dreaded cracked FH, thus the reason for the FH changes initially.

Nez

GreatPlainsRifleman

Thanks for such a detailed write-up, Bamban. That rifle sounds like a dream to play and experiment with.

Do you mind if I ask you what kind of hold you use on the SR target?

Bamban

6 o'clock normally, in standing I do sub or sub sub six hold when windy. Basically aiming in the middle of the white, cranking additional 2 minutes of elevation

levisdad

Thanks for sharing all the info!

What's different about your obermeyer reamer?

Bamban

The neck is 0.341 instead of some which are 0.344, to minimize neck workout. Your typical ammo measures around 0.337 at the neck. My AR10s are chambered with this reamer. The freebore on mine is exactly 0.3080 instead of the 0.3085. The bullet is encapsulated in its own diameter. Check out the spec on the famed Wylde chamber, the freebore is 0.2240. Bill had the right idea, regardless of the runout is on loaded ammo, the slug will start with no yaw because it is wrapped in its own diameter.

Phil McGrath

Auhh, some chamber dimentions can be pretty generous, did you meen too say .3435 at the neck for typical ammo? .377 is pretty big even for a std chamber neck of .3445?

I bet my ammo would work good in a Obermeyer chamber, my ammo mic's in at a neck dia. of .337 and that fits into a .341 hole nicely.

Bamban

That meant to be 0.337 neck dimension of loaded rounds. Good catch, thank you.

Bamban

Phil,

The standard Obermeyer reamer is not 0.341 at the neck, it has the standard neck dimension, I think 0.344

jmoore

Just checked a Clymer reamer: 0.346" neck dia. Huge!

Bamban

That is huge. The necks will get a good workout. If you ever want to try my reamer someday I'll be glad to send it to you. No promise on any accuracy of the finished rifle, just the risk on your part. It is available if you want to play.

Nez

Phil McGrath

Thanks Nez for the update, when I built my double lugged rifle the chamber was cut with a M852 reamer it worked well but with some guys running with the 185 Bergers the leade angle may not be the best agreement for that chamber. I need too look at where there not the same M852 vrs Ober M118, a gentle leade angle takes alot of preasure off of the chamber.

I have a long way too go before I put the next one together.