Precision Rifle HELP!

[Muzzy100]

Precision Rifle HELP



Hey guys I have a question that I need some serious help on.



I have built a custom 308 rifle. The rifle is based on a 700 short action. The action and bolt face have been blue printed and trued. I put a Bartlein 1/10 twist barrel on the rifle. The rifle is in a XLR Element Chassis.



The rifle is doing some weird (unacceptable) things that I am trying to resolve. So the rifle will shoot several groups as a custom rifle should stacking rounds and mostly shooting one hole groups. Then out of the blue the rifle will start shooting over an inch at 100 yds. The issue happens regardless if the barrel is clean or dirty or warm or cold bore shots. I cannot figure out what is causing the rifle to shoot perfect then shoot horrible. I have had other shooters that are professional marksman shoot the weapon and the same problem occurs when it is shot by the other shooters.



I was under the impression that if it was a scope/scope mounting issues that there would be no consistently and it would shoot sporadic all the time (but I could be wrong I don’t know). The only other thing that it may be is the chassis. A friend of mine has the same chassis and his gun was doing some weird things and he removed it from the chassis and his problems were resolved. So what does the green screen say?? What could some of my problems be and or advise on going about fixing said problems. I have so much money and time invested in this gun I have got to figure this out.



Unfortunately I don’t have another top quality scope laying around to throw on the gun to see if the scope is the issue. Nor do I have a spare quality stock lying around that I can drop it in. I do have a factory houge that I plan to place it in temporarily and see if the problem continues.



For what it’s worth I am shooting reloads and have been reloading for years and never had an issue. Besides that goes back to my original point why would its shoot 3 or 4 perfect groups of one hole then go crazy and can’t shoot at all. Feel like if it was an ammo issue it would be consistently sporadic, not perfect then horrible.



When the gun is shooting well it is maintaining half MOA out to 300-400. But of course when it is shooting weird it’s all over. HELP thanks,



Muzzy100

[az2tx]

What glass?
what bullets
Skim bedded into chassis

[hoythitman]

Sounds like a bedding or a optics problem. Sometimes they are constant sometimes they are not. I had a scope issue and it did something similar. It would shoot 2 or 3 out of 10 off by an inch or two. The other 7-8 were .3moa, it wasn't a scope mount problem, the actual scope was bad. It was a brand new nightforce, so don't think your scope is perfect because of the brand. Change the scope out and see if it persists. Torque all of the bolts on the chassis to spec, if you are in SA area and don't have tools I have torque wrench and more than happy to help.

I run a 308 in a XLR chassis as well. I recall the torque was a lot higher than on most stocks, might not be torqued as tight as it should be.

[catslayer]

Here is the order of operation in where I could see issue

1.) shooter, we all have bad days(though you said multiple shooters so lets cross it off)
2.) Ammo... Different lots of powerder, old powder, powder that got wet, different brands... ALL things that can effect group size and POI
3.) Scope... Something loose in there, that said, a loose scope doesn't typically act funny then go back to zero...

I'm still not 100% percent sure I understand your issue... It "randomly" will throw a terrible group followed by great groups?

How often?
Mostly good groups?
Is it positional- I mean does it throw worse groups when shooting prone vs a table???
What chassis???? -> I'm a dumb@ss I see it now... XLR... hmmmm

Honestly sounds like ammo inconsistency to me... Powder issue specifically... Are the "Bad groups" roughly around the zero? Just wider groups? Or are they off in any consistent direction?

My next guess... There is something in the way you and the chassis are holding the gun that is torqueing the action.

I've never PERSONALLY seen a bad scope, but hear about them so I could totally see hoythitman being right...

Ok weird stuff I've seen that MAYBE effect it... Saw a mini 14 that would throw the LAST bullet in the clip BADLY. Only the last bullet, because when the Magazine had rounds loaded the top bullet would put pressure on the back of the bolt. That thing would shoot 29 rounds in a dime... then that last one... only God knows where it would go... This story goes basically with the torque idea...

[Slick8]

I agree with above.

Not sure of the bedding requirements of your stock but;

Ensure it's properly bedded (you may wish to re-bed to be sure)
Properly torque all action and scope attachments
If the problem persist-SCOPE.

BTW-You don't have to have a top end $1k plus scope to try this out. If you or a buddy has a scope that will fit your rifle of known performance-that's all you need.

[Cajun Blake]

never been a fan of the chassis system stocks

they're made to "drop-in" yet you don't have 100% contact between the action bottom and stock

[SOLID EAGLE]

I had the same problem with a Savage 308 in an XLR. After scratching my head for a few weeks, I started re-torquing ALL of the screws, action, base and rings. I soon discovered my rings were coming loose after a few shots. I have Ken Farrel rings and I had put locktite on the screws. I was told by someone to remove the locktite and then re-torque the screws. It hasn't moved since.

Something is loose. Take your torque driver with you next time you shoot. When you get a round that hits out of the group, re-torque everything. You will find the problem I'd bet.

[az2tx]

never been a fan of the chassis system stocks

they're made to "drop-in" yet you don't have 100% contact between the action bottom and stock

Skim bed just like an aluminum bedding block

[BrianL]

my first guess is ammo, second would be scope mounts, third stock torque changing someway.

[trophy8]

I got $20 that it's a bedding issue and that it's moving. Torque it all properly. 40-60 in #s. I'd ditch the chassis all together IMO.

[hoythitman]

I got $20 that it's a bedding issue and that it's moving. Torque it all properly. 40-60 in #s. I'd ditch the chassis all together IMO.

That chassis is 65# torque

[trophy8]

That chassis is 65# torque

Then 65. That shows they probably know it moves.

[hoythitman]

Then 65. That shows they probably know it moves.

I don't understand the logic, but ok.

I was under the impression that it was because of the material. Wood and laminate have the lowest torque, then fiberglass, then alum bedding block. I have an XLR chassis, shot it before bedding and after, groups were the same. No flex, good fit, and a less $$$ than a Manners or McM with a DBM system.

Ps. Manners mini has a 65# spec too..... Must be garbage

[Muzzy100]

Here is the order of operation in where I could see issue

1.) shooter, we all have bad days(though you said multiple shooters so lets cross it off)
2.) Ammo... Different lots of powerder, old powder, powder that got wet, different brands... ALL things that can effect group size and POI
3.) Scope... Something loose in there, that said, a loose scope doesn't typically act funny then go back to zero...

I'm still not 100% percent sure I understand your issue... It "randomly" will throw a terrible group followed by great groups?

How often?
Mostly good groups?
Is it positional- I mean does it throw worse groups when shooting prone vs a table???
What chassis???? -> I'm a dumb@ss I see it now... XLR... hmmmm

Honestly sounds like ammo inconsistency to me... Powder issue specifically... Are the "Bad groups" roughly around the zero? Just wider groups? Or are they off in any consistent direction?

My next guess... There is something in the way you and the chassis are holding the gun that is torqueing the action.

I've never PERSONALLY seen a bad scope, but hear about them so I could totally see hoythitman being right...

Ok weird stuff I've seen that MAYBE effect it... Saw a mini 14 that would throw the LAST bullet in the clip BADLY. Only the last bullet, because when the Magazine had rounds loaded the top bullet would put pressure on the back of the bolt. That thing would shoot 29 rounds in a dime... then that last one... only God knows where it would go... This story goes basically with the torque idea...

Say out of 30 rounds it would shoot 2-3 five shot groups good then the next two groups will go from one hole to over an inch and no consistentency as to a side or direction it will be left right up down of the bull. I am not ruling out shooter error but I just don't think that is what it is. I am shooting a 175 seirra match king out of Lapua brass behind 43.5 grains of varget.

[Muzzy100]

I have not altered the chassis in anyway it looks difficult bed the way it's set up.