Please Help me problem shoot My 7LRM

[Sneekeehunter]

The gun:
Remington 700 action trued
Sako extractor bolt modification
26" Proof Sendero light profile 1-9 twist barrel with titanium MB
Jewel trigger
AG composited Carbon fiber stock with aluminum pillars and glass bedded.
Leupold VX-6 4-24X52mm

The problem:
I usually shoot groups of 4 shots. two shots will cluster on one side of the target and two shots will cluster on the opposite side. I will post pictures in following comments to show what I'm talking about.

For example. Shot #1 will be left of dead center, shot #2 will be right of dead center, shot #3 will cluster right next to shot #1 and shot #4 will cluster right next to shot #2.

Generally Looks like this: 1,3 X 2,4

I just had this rifle finished in late July. I started by working up a pressure test ladder from 67 grains of H1000 up to 72.8 grains. I then performed a 300 yard ladder test with my pressure window of 69-71.5 grains. Then again at 500 yards after narrowing it down further by .02 grn increments. I identified the node sweet spot was about 70.2 grains for Hornady 175 ELD-X using Federal 215 M primes.

It shot a 3" group at 500 yards and I though ****!! I'm happy with that so I backed down to 200 yard and started loading up 3 shot groups of different seating depths. I was in for a huge surprise. The best group I could get at 200 yards regardless of seating depth was about 3". I tried shooting it dirty and I tried shooting it clean with no change in results.

I noticed that the bolt release was making contact with the side of bottom metal in the trigger housing preventing the bolt catch from working properly. If the bolt release was depressed the bolt catch would work properly but it would not spring back up allowing the bolt to essentially fall out of the rifle. I went to work on the bottom metal and removed enough material for the bolt release to perform properly without making contact with any part of the rifle. I also made sure that no part of the trigger was touching the stock or bottom metal. I did notice that the bolt catch does appear to have a slightly rounded over edge and if the bolt is wiggled just right it will still slip over the catch and the bolt is removed without catching on the bolt catch. (I don't think this is affecting the accuracy but maybe I am wrong. I'm going to install a new bolt catch to see if that resolves that problem.)

I tired different powder combinations of Retumbo and different primers (CCI 250's and Remington #9's). There was huge differences in SD and ES. The retumbo was about 50-100 fps slower consistently.

Upon a suggestion from a friend I started weighing the Hornady 175's ELD-x's. I noticed quite a bit of difference in weights ranging from 174.1 up to 175.9. After sorting the bullets my results improved down to about 2" group at 200 yards but they were ugly. Not suitable so I decided to switch to the Berger 180 VLD.

I ran another ladder and found the sweet spot to be 70.5 grains of H1000 and Fed 215m primes. It shot better but not much. This is when I started noticing the above stated pattern. Again, I tried different seating depths and charges trying to figure it out but nothing really shined. I ran them .010 off up to .080 off.

Next I switched to Berger 180 Hybrids thinking the seating depth may not be as temperamental. This definitely helped shrink the groups down under 2" at 200 yards but I was still getting the same weird results.

I decided to pull everything apart. First I bedded the scope bases (Running Night Force 20 MOA Pic bases and rings.) Then I noticed the bottom metal wasn't making contact with the stock evenly. If the rear action screw was tightened just to the point it was making contact with the stock then the front action screw would need to be tightened about 1/8 of an inch before it made contact with the stock. I properly bedded the front area under the bottom metal to relieve this stress. I thoroughly inspected the bedding area to make sure nothing was moving rubbing or causing excessive pressure. The action fits in the bedding like a glove with no pressure. I even coated the recoil lug with lipstick to make sure the bedding around the lug was proper. It appeared to be perfect from my perspective. (the recoil lug is making contact on all sides. Contrary to my normal bedding procedure and after consulting with my smith I did not use any tape on the back or sides recoil lug when bedding the action. [Bedded in Devcon]) I made sure the barrel had plenty of clearance from the stock. 1/8" all the way around Perfect.

I installed the bottom metal and made sure the mag was not binding with the action or the bottom metal and proceeded to torque everything down.

I torqued the action screws down evenly to 45lbs and torqued the scope bases to the action at 25lbs and the NF cross bolt to 68lbs. Torqued the scope into the bases at 25lbs.

Took it back to the range. This time it shot the same pattern in a different order. the group was almost exactly 1" at 200 yards. I tried it at 500 yards just to see what it was doing and it shot a 1 MOA group at 500 (5"). I'm nearly satisfied with this result for a hunting gun However, it drives me nuts that its still shooting the same pattern. the clusters of shots are touching usually and this tells me that the gun can shoot lights out but I still feel like something is causing this anomaly.

Can someone help explain to me this weird anomaly I am seeing in my targets? At first I thought it was either the scope or the bases moving but now after the changes I've made I'm sure that's not the case. It could be the scope and I plan on putting a different scope on it after the season when I have more time to play with it. I'm also going to try a different stock just for fun.

The group will be not as obvious in some of the following targets so I circled them to help. These were different seating depths or different charges.

Right now the most current load is: 70.5 grains of H1000, Berger 180 Hybrid COAl 3.403, Ogive 2.682, Federal 215m Primes, Hornady Brass.

I also started annealing and sorting my brass which has helped but I need to experiment with this more. I'm now getting way more consistent neck tension. I think I could revisit the Hornady ELD-X after sorting and annealing the brass. It might help some but I'm not sure if it will help enough.

Thanks for any help or advice you can offer.

Dan

 

[Sneekeehunter]

All of the following targets were at 200 yards

I shot from a tripod with a sand bag from a bench as seen here: very solid rest. I've been told by very proficient competition shooters that I have good form. I'm not new to this game and have shot and built sub minute guns. I am not an expert tho and I will take any advice I can get. I've tried different shooting techniques also. This gun definitely likes being held down.

 

[Sneekeehunter]

 

[Sneekeehunter]

The top right hole was cold bore

 

[Sneekeehunter]

This was the last group I shot

 

[ShtrRdy]

It sounds like you've tried most everything I would try. You might look at the following:

- check the muzzle break to make sure it's still tight.

- increase action screw torque to 55 in-lb

- check to see if the recoil pad is loose.

- have you used the tripod rest set-up before? Could there be some inconsistent behavior?

- If all this looks good, remove the barreled action from the stock and take a close look at the bottom and sides of the action. Try to see if there are any areas that seem to have been rubbing. This might indicate that the bedding isn't providing a balanced no stress mounting interface.

 

[Sneekeehunter]

It sounds like you've tried most everything I would try. You might look at the following:

- check the muzzle break to make sure it's still tight.

- increase action screw torque to 55 in-lb

- check to see if the recoil pad is loose.

- have you used the tripod rest set-up before? Could there be some inconsistent behavior?

- If all this looks good, remove the barreled action from the stock and take a close look at the bottom and sides of the action. Try to see if there are any areas that seem to have been rubbing. This might indicate that the bedding isn't providing a balanced no stress mounting interface.

Thank you for the advice. I did just that tonight before even reading your post!!! Great minds think alike! Actually a friend suggested tightening down the action to 65ft lbs. I removed the action and closely inspected all te parts. I'm attaching a few pictures. Everything looked fine with the exception of two small areas. If you lop closely you can see what I'm talking about. In the bottom back side of the recoil lug the Cerakote is rubbed off just the tip of the corners. That is the only spot I noticed anything at all and its minuscule!

 

[Sneekeehunter]

It looks the same on both corners. I also drilled out the action bolt holes to make sure they weren't making contact with the bedding in the action or pillars.

Lastly, I inspected the bolt catch and remedied that problem. The Jewel bolt release tab wasn't making contact with the bolt catch properly. There is a slight notch in the back of the bolt catch were the bolt release tab should rest and when the release tab is depressed it pushes up against that notch in the bolt catch and lowers the bolt catch away from the bolt. Well the bolt release tab was about 1/16" forward of that notch preventing the catch from fully raising up to stop the bolt. A little persuasion with some needle nose pilars into the proper position and she works like a charm!

 

[rafterfp]

IMHO I would try shooting with a good quality front rest/bag. Let it recoil and see what happens.
I have seen bipods/tripods cause some quirky stuff by not letting the rifle recoil the same way consistently. Just a thought.

 

[Sneekeehunter]

Forgot to mention I have checked the muzzle brake several times and it's never been lose although I have never shot the gun without it.

Also yes, I have shot a number of different guns from this same tripod set up. In fact the same day I shot the last target posted I also shot my 300 RUM from it and shot a 1/2" 4 shot group at 200 yards. The second best group I've ever shot with that gun. I've also shot multiple 1/2 moa groups from 100 out to 500 with it on my 6.5 Grendel.

 

[Sneekeehunter]

IMHO I would try shooting with a good quality front rest/bag. Let it recoil and see what happens.
I have seen bipods/tripods cause some quirky stuff by not letting the rifle recoil the same way consistently. Just a thought.

I'll give it a try!! Can't hurt right?!?!

In my experience it's usually the shooter that being inconsistent not the bipod or tripod. Usually inconsistent cheek pressure, forward pressure, over gripping the gun, under gripping the gun and on and on and on. I'm not perfect and I could be doing any of the above but I think my results on paper would be more sporadic. Hell I don't know!!! I'm willing to try anything tho!

 

[rafterfp]

For me it's almost always the shooter haha, if I'm having trouble with a known shooter I always start going over my fundamentals. It usually corrects my problems. Good luck man, beautiful rifle by the way.

 

[bigngreen]

First thing I'd do is find an optic that does not have Leupold on it, I've had more rifles come in shooting like poo that were solved by pulling of a Leupold it's kind of my first thing to try. LRM brass is crap, IMO it needs neck turned and sorted, my buddy and it build two of them, both of us decent gunsmiths and the reamer set up for a turn neck with the right throat and they shot very well but no where near what that case should be capable up with decent brass.
When I see double grouping I really suspect an optic or mounting system!

 

[Sneekeehunter]

First thing I'd do is find an optic that does not have Leupold on it, I've had more rifles come in shooting like poo that were solved by pulling of a Leupold it's kind of my first thing to try. LRM brass is crap, IMO it needs neck turned and sorted, my buddy and it build two of them, both of us decent gunsmiths and the reamer set up for a turn neck with the right throat and they shot very well but no where near what that case should be capable up with decent brass.
When I see double grouping I really suspect an optic or mounting system!

This was my first intuition as well. I'm hoping to try a different scope after the season. This is at least my 10th Leupold scope and the vx-6 was the best I could afford at the time. I'm thinking of trying to sell it an put on a Sig Tango 6 after the season. I'm also going to try a McMillan stock after season just to make sure it's not my stock or bedding.