What is my next step?

B

Bnhpr

Ben Hooper
I just completed a rifle last week (see pic)

It is a 6,5x284, Rem 700 LA in a laminated stock. The bbl is a #4 contour, 8" twist, cut rifled, 27" SS

I checked my work, chamber runout is low, headspace is good, brass looks good. The reamer has built 2 other very accurate rifles on #7 and HV barrels.

I was very pleased with the bedding. Scope is in good shape. etc. etc. I've checked everything.

I have 50 rounds through it, Lapua brass, necks turned, 142SMKs and 140 VLDs. This load shoots very well in the other rifles 8 twist same barrel mfg.

My new rifle shoots a 1" to 2" group at 100 yards. Best it will do. 2 may touch, then bang, its 2" out on the 3rd shot. I re-crowned it, checked chamber runout again etc etc. Put the barrel back on. No change.

The bore looks shiny, doesn't copper up... I checked the twist rate. I just have no idea what to do next..besides contact the MFG?

I do have some 120 grain bullets on order, but I cannot imagine I would get this thing back on track, by simply going to a shorter bullet.

Any ideas from the gunsmiths appreciated.

Ben
 

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I had a 6mm-284 do this crap to me once. It was an Obermeyer barreled Nesika K action in a big ol rail road tie bench stock built for whackin pups. He and I scratched each other's heads for the better part of an hour over the phone about it.

In the end one of my employees pointed out that the headspace was a smidge tight. It was a fluted barrel and in the effort to get the flutes timed I had given it an extra grunt to get it there. It was just enough to send the headspace from "GO+.001" to a red one under "GO."

We pulled the barrel, squeaked the chamber with the reamer, and then thie biche suddenly came to life and behaved itself. It went from MOA+ groups to itty bitty ones that bring big smiles.

It may sound a bit far fetched and it really made me puzzled, but that is seriously the only thing that was changed. It had close to 200 rounds through it as I was told by another guy that Oby barrels sometimes take a while to come in.

Just maybe your in the same boat.

Good luck.

Chad
 
Thanks Chad, I actually considered trying that, but have not actioned on it.
I had a 257 roberts that responded favorably from that. (I have a post on it somewhere)

Question: My brass is growing .0015" after resizing, and the bolt closes not firm, nor easy, but in between...do you think I would be ok by reaming out another .002" or so?

Do you see any problem with a T-tap handle and doing it by hand?

Ben
 
Bnhpr said:
Question: My brass is growing .0015" after resizing, and the bolt closes not firm, nor easy, but in between...do you think I would be ok by reaming out another .002" or so?
Click to expand...

Ben,

Strip the bolt and insert a Go Gauge. If it's to tight to close or you have to force it closed then yes. If it's snug on a Go but you can still close and open with your pinky finger I'd leave it as is.

Have you ran a load ladder on this rifle or is this a pet load? The load may simply be out of tune for the rifle.
 
wnroscoe said:
Ben,

Strip the bolt and insert a Go Gauge. If it's to tight to close or you have to force it closed then yes. If it's snug on a Go but you can still close and open with your pinky finger I'd leave it as is.

Have you ran a load ladder on this rifle or is this a pet load? The load may simply be out of tune for the rifle.
Click to expand...

I ran 49-51.5 of H4831sc and .010 jump to .008 jam over 25 rounds... No change..no pressure problems

It closes quite easy on go and resized lapua brass. I compared it to my F class and I would say it closes very similar to it. Feels good to me.

I tighten the barrel with an action wrench and barrel vise. I put a little molykote on the threads and tighten it by feel.
 
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Did you do anything to the the action? Can we see a picture of the bedding? How did you check it for correctness?
 
Boyd Allen said:
Did you do anything to the the action? Can we see a picture of the bedding? How did you check it for correctness?
Click to expand...

I don't have a pic of the bedding, but I gave it a visual inspection. A good bedding job leaves the compound with a shiny, clean separation. I clean off any stuff that protrudes into the magazine or trigger well with an x-acto...look the action over carefully for kling-ons and when I put the action in, I put it in without the magazine box first so I can see it touching completely. After assembly, I check for air gap around the bbl and wiggle it to make sure there is no movement. I have bedded 50 or more 700's and I am quite comfortable doing so. I am very confident this is not a bedding issue.

I put the action on a mandrel and between centers on the lathe. I skim off the face of the action only enough so there is new metal and the chop saw marks are gone. This gives me a square face to tighten the lug/barrel onto. This is a B serialed action and looked good.
 

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I've bedded dozens of 'em myself. Have you checked to make sure the front action screw is not bottoming out? Just a thought. How about the scope and mounts? I know all this is elementary, but sometimes simple things get overlooked. Don't mean to offend you.
 
A friend (who has built several good shooting rifles) just went through an expensive and time consuming time trying to get a Remington actioned, custom barreled .204 Ruger to shoot. He had done what you have done. After putting on his second barrel, to no avail, a friend suggested that he look at his action threads. He turned a false tenon with a shoulder that was as tight as he could make it and still turn the action onto it by hand. when the front of the action touched the shoulder, there was light showing 2/3 of the way around the action face. After the threads were carefully single pointed one of the barrels was refitted, and it shoots like a house a fire. I know that many gunsmiths have gotten away with just facing actions, but this one example made a believer of me. As to your bedding job, they can look good and still have significant problems.
 
Bnhpr said:
I ran 49-51.5 of H4831sc and .010 jump to .008 jam over 25 rounds... No change..no pressure problems

It closes quite easy on go and resized lapua brass. I compared it to my F class and I would say it closes very similar to it. Feels good to me.

I tighten the barrel with an action wrench and barrel vise. I put a little molykote on the threads and tighten it by feel.
Click to expand...
If you have not tried different loads, like a ladder test as wnroscoe suggests, I'd try that next, say in 1/2 grain increments. Do this and I'll bet the performance will change. That #4 is not going to act like a #7 or HV.

"Pet" loads only worked for Ken Waters.

About how tight do you think your tight by feel is?
 
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Well since this is a new gun that's had a bunch of work done to it, it kinda' sounds like it's time to start eliminating things.

1. Is the barrel on tight? (is it?)
2. Is the bolt handle touching the stock?
3. If it's a repeater, is the mag box able to wiggle between receiver/floorplate?
4. Is the recoil lug on square to the receiver?
5. Are your guard screws "falling into place" or are they binding during assembly?
6. Are the scope mounts tight?
7. Is the front scope mount screw crashing into the barrel tennon thread?
8. Is your bolt shroud/bolt thread fit decent?
9. Is there anything in the bedding that could act as a secondary recoil lug?
10. Are the optics working right?

Good luck.

Chad
 
1. Is the barrel on tight? (is it?)

Yes, I've had it off 3 times, and It is definitely tight

2. Is the bolt handle touching the stock?

No


3. If it's a repeater, is the mag box able to wiggle between receiver/floorplate?

Yes, the clearance seems right, and the action is tight in the bed.

4. Is the recoil lug on square to the receiver?

The mating looks good and feels good when tightened

5. Are your guard screws "falling into place" or are they binding during assembly?

They are easy to line up

6. Are the scope mounts tight?

tried 2 different mounts and scopes

7. Is the front scope mount screw crashing into the barrel tennon thread?

no, I always check this


8. Is your bolt shroud/bolt thread fit decent?

I have not checked..but I have never had a problem here before?


9. Is there anything in the bedding that could act as a secondary recoil lug?

no, I've looked very closely at the bedding.

10. Are the optics working right?

Tried 2 scopes and mounts, I always test sight in and fire rifles with a set of burris bases and a cheap Bushnell 18x scope. This rifle, I put a proven 4-16 Nikon tac scope on after.
 
Thanks for the ideas guys, and I am going to recheck every point you have made here when I get home.

Also, I have a proven LA stock that has a aluminum bedding block that I have used to eliminate bedding from the equation. Normaly everything stays tight in it. I have tested some very good shooters in it. I'll try it.

My instinct tells me there is something wrong with the barrel, or my machine work, but statistically I know that bedding is right up there.

The gunsmithing gods have been hard on me for this one......


Ben
 
Bnhpr said:
Thanks for the ideas guys, and I am going to recheck every point you have made here when I get home.

Also, I have a proven LA stock that has a aluminum bedding block that I have used to eliminate bedding from the equation. Normaly everything stays tight in it. I have tested some very good shooters in it. I'll try it.

My instinct tells me there is something wrong with the barrel, or my machine work, but statistically I know that bedding is right up there.

The gunsmithing gods have been hard on me for this one......


Ben
Click to expand...


If your gut is telling you that it is the barrel, then do you have another proven Remington style barrel that you can screw on and fire in order to isolate the barrel problem from the action/stock/scope components, or fire the new barrel in another proven Remington action/stock/scope assembly.

Always troubleshoot by isolating and eliminating the major components barrel/action/stock/scope assemblies.

Sounds like you have done this with the scope/mount assembly, now follow through with the barrel/action/stock items.....................Don
 
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Don said:
If your gut is telling you that it is the barrel, then do you have another proven Remington style barrel that you can screw on and fire in order to isolate the barrel problem from the action/stock/scope components.......................Don
Click to expand...

Hmmm...I have a pile of factory barrels that wouldn't touch the stock...but I'm not sure they will do much better than 2". And a 308 win Broughton that is a great shooter...but is too big for the stock.

Maybe after trying the new stock, if it still shoots crap, then I'll screw on the Broughton and if it comes alive, well...the barrel is the problem.

all this dependent if the headspace is not too tight.

Ben
 
How is the fit of the bolt nose into the barrel counter bore?
You don't want the barrel touching or near enough that it touches when the chamber is loaded.

Got clearance??
 
Ben, have you checked your bedding job with a dial indicator between the barrel and forend? A bedding job can look good, but a dial indicator will tell whether the action is laying in the bedding stress free. I consider anything under .002" movement between barrel and forend good. If there's more movement than that then I rebed. Usually, all you have to do is loosen off the front receiver screw and the dial indicator will show whether the bedding is good or not. Holding the rifle vertically or upside down horizontally (resting the barreled action in a gun cradle) will work to test the bedding. On a small contour barrel, two flat pieces of steel bolted together clamping onto the barrel will help hold a magnetic indicator base in place and steady. It helps to drill out the guard screw holes to 5/16" to make sure that the guard screws aren't touching inside the pillars or stock if there aren't any pillars. A rifle that won't shoot can cause you to doubt a lot of things. Hopefully, they are few and far between.
 
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