POI changes as barrel warms up - need advice

[mjgillen]

Hi all!

I'm shooting out at 300 yards in a match and I can see consistently that the first 3 or 4 shots in a 15 shot string are all over the place. We start a string with two sighters then move to target for 15 shots on target. The first few on target are always off (not in the 10 ring) then the gun settles down and the remaining shots are quite consistent on target.

Any ideas? What to check? Adjust?

The rifle started out as a Savage 12FV .223 Cabela's special. However in its current configuration the only "origina" part is the Savage 12 "varmint" action (NOT a Precision Target Action). I bought and installed from James at Northland Shooters Supply a "prefit" Shilen .223 Match barrel, match barrel nut, match lug, Savage "F Class" stock, tools and headspace gauges. Everything is bolted together per torque specifications using a torque wrench.

Looking for advice from the community.

Thanks,
Michael

 

[CharlieNC]

By your description I "assume" this is not just on a clean bore, but also subsequent strings. The traditional advice is assure the barrel is completely free floated, and bed the action; but not the tang on a Savage. I'm not familiar with that stock but have seen them shoot extremely well.

 

[mjgillen]

You are correct this is NOT a clean bore - after several sighters.
Yes, the barrel is free floating. I checked.
Action is not bedded.
Seems like a heat thing however I am not sure how to try and resolve it.

Michael

 

[CharlieNC]

Is there a metal bedding block, pillars, or just wood?

 

[mjgillen]

Pillars. This action has two screws only. The Savage PTA has three screws.

 

[CharlieNC]

I would dremmel out the stock to bed the recoil lug and front of receiver. Look for uneven witness marks as evidence of fit issues. While removed check torque on barrel nut, scope rail, etc.

 

[C.E.Smith043]

Are you shooting any kind of coated bullets?

 

[Ggmac]

You are correct this is NOT a clean bore - after several sighters.
Yes, the barrel is free floating. I checked.
Action is not bedded.
Seems like a heat thing however I am not sure how to try and resolve it.

Michael

After several sightseers is a bit confusing . Was it cleaned then several sighters ? If so I'd see what happens if you only run a patch thru the bore instead of a full clean .
Make sure nothing is touching the stock , trigger , bolt handle , barrel of course , action screws , etc

 

[savagedasher]

This was common for as long as I could remember . Many of times it was a barrel that was straightened and not normalize after . with heat it returns to where it was straightened from . Larry

 

[mjgillen]

Are you shooting any kind of coated bullets?

Nope. Berger 80.5gr full bore match bullets. Lapua brass, CCI 450 primers. varget powder.

After several sightseers is a bit confusing . Was it cleaned then several sighters ? If so I'd see what happens if you only run a patch thru the bore instead of a full clean .
Make sure nothing is touching the stock , trigger , bolt handle , barrel of course , action screws , etc

Its usually squeaky clean before the match starts. Then we have unlimited sighters, of which I shoot about 10. Then we shoot the match, which is 2 sighters, then 15 for record. Then we go out and change the targets which takes about 30 min which allows the rifle to cool down.

I am consistently seeing the 2 sighters go 4-6" away from each other, usually in opposite directions such as first one low to the right then the second one hight to the left. After a few more shots the rifle settles down and consistent POI. However when the rifle is cool(er) not very consistent.

Sometimes I am shooting on a bipod, sometimes on a rest with bags. I am pretty confident in the other equipment, bags, bipod, scope, etc. Its just that the point of impact changes radically from when the rifle is cool to when it has warmed up.

Looking for advice on how to diagnose. Should I just pop off the stock and tighten the Savage barrel nut as a starting point? Then when reattaching the stock make sure its tightened to the proper torque?

Thanks,
Michael

 

[mjgillen]

This was common for as long as I could remember . Many of times it was a barrel that was straightened and not normalize after . with heat it returns to where it was straightened from . Larry

That makes sense. So send it back to Shilen?

 

[Nowhere Man]

Let somebody else shoot it and see if it does the same thing.

 

[mjgillen]

Let somebody else shoot it and see if it does the same thing.

I did. Me and my son both shot it at the match yesterday with the same results.

 

[billlarson]

Squeaky clean no good.....LIGHTLY LUBE BARREL... with lok-ease or kroil..... repeat.... LIGHTLY.....
I would look for something that is loose.....
disassemble gun.....from stock...scope off...rings off...rail off......
when bedding be sure to use a release agent.....
OR...
as I do....... no release agent...as it takes only minutes to get a glued in part BACK apart.....
CLEAN ALL PARTS.....
skim bed clean action to clean stock......
clean rail ..... bed to receiver......
check torque on barrel...... minimum headspace.....
reassemble gun.....look at rings...... lap them....bed them to scope.....
use good ammo and re-zero...... if problem still exists..... call shilen......
bill

 

[500Stroker]

Hi all!

I'm shooting out at 300 yards in a match and I can see consistently that the first 3 or 4 shots in a 15 shot string are all over the place. We start a string with two sighters then move to target for 15 shots on target. The first few on target are always off (not in the 10 ring) then the gun settles down and the remaining shots are quite consistent on target.

Any ideas? What to check? Adjust?

The rifle started out as a Savage 12FV .223 Cabela's special. However in its current configuration the only "origina" part is the Savage 12 "varmint" action (NOT a Precision Target Action). I bought and installed from James at Northland Shooters Supply a "prefit" Shilen .223 Match barrel, match barrel nut, match lug, Savage "F Class" stock, tools and headspace gauges. Everything is bolted together per torque specifications using a torque wrench.

Looking for advice from the community.

Thanks,
Michael

How did the rifle shoot out of the box? Before you made any changes.

 

[saw-tooth-jimmy]

I would cryotreat the barrel and action at sub-zero I think out of Minnesota. They heat treat and then cryogenic after. Then I would clean barrel before the match and put 20 to 30 down range then it is ready to take to match. Don’t clean at match unless put 100 rounds down range. My opinion probably not match up with everyone but works for me.

 

[joed49]

Sounds so familiar. I had a Savage 12 VSS that did the same thing. Drove me nuts for 5 months till I cured it. Sold it and bought something else.

When I talked to my gunsmith about it he told me that Savage rifles are very accurate out of the box most times. The small percentage that have problems are usually bad problems. His advice was to try adjusting the bedding and if that didn't work sell it, which I followed.

I tried a lot of things and none worked. My rifle would shoot the right side of a V starting at the bottom working to the top.

 

[GSPV]

Usually a symptom of stress in the system. Possibly, but not likely, given the presentation of symptoms, the scope.

I’d try another scope. I’d bed the action correctly.

If those didn’t help, I’d punt and find a rifle proven to shoot.

Don’t throw good money after bad.

 

[Texas10]

I've bought 5 model 12FV's in the last 2 years and used them to build with using same components you mention, so I know what you're going through. And although I am no gunsmith, or competition shooter, I will offer my suggestions regardless, with the usual disclaimer that they are probably worth every penny you paid for them...hehe.

I noticed on all my actions that the front face is knurled, with raised edges (flashing) present, and I suspected that was causing my POI shift while the barrel heats. So I took one of my actions to a GS and had it trued. That seemed to work well to prevent POI shift.

While building another action, I lapped the front face with 1000 grit while inspecting it closely every few strokes for signs of any high or low spots. Didn't have any, but I did get a very flat surface for the precision recoil lug to bear against.

Carefully free floating the rear tang is very important, as is torque tuning during initial trials.

Bedding in and around the pillars is crucial, the rear one being the hardest to get full support without interference to the sear. You might look very closely at the right side of the stock around the sear and check for any signs of wear that might indicate the sear is rubbing against the stock or bedding.

Also, when you place the barreled action back in the stock, make sure it's aligned perfectly and no part of the tang is touching. I use a .005 feeler gage and slide it under tang to make sure nothing is touching.

Lastly, look for a good used target accutrigger, and put your varmint trigger in the parts bin.

 

[Zero333]

Add 0.2gr of Varget to your load and see what happens.

Maybe the load is at the edge of the node and comes into the node once things get more heat in them and help generate that little bit more pressure.

Just a guess.

Glass the action and make sure to glass a bit passed the barrel nut. Like 1" passed the nut.