Sako A3

[Maineiac]

Thanks for taking the time to read this. I shoot a Sako A3 in 338wm with a radial muzzle brake, I roll my own in terms of cartridges and currently I’m shooting 204 grain hammer hunters. I’ve got a vx6 3-18x50 on top.

My question is: Why does my cold bore shot deviate more than 3” at 100 yards from subsequent shots. Is it an issue of bedding and free floating? Maybe it is the nature of this gun. It hasn’t caused me a problem in the woods yet, but eventually I’ll forget to compensate and I’d like to avoid that situation. Thank you for your thoughts and advice.

 

[ResearchinStuff]

My guess: scope problem. Your zero is drifting while you drive around, and the heavy recoil of that first shot is repositioning your erector. This is fairly common with leupolds.

 

[Maineiac]

Perhaps, here are some more details though. The first shot at the range is consistently low, on multiple different trips, at different temps. It consistently hits 3” low at 100 yards for the first and then consistently at point of aim for the follow up shots. Would the erector problem you suggested cause variable POI from trip to trip or would it the erector drift consistently into predictable positions? If it’s as easy as sending the scope in I’d be pretty excited!

 

[ResearchinStuff]

That is awfully predictable to be any common quirk. Still worth testing using a known good scope just to eliminate a potential issue.

 

[Maineiac]

Put a different know scope on the gun and the results were the same. It shoots the first round as desired and then the string starts climbing vertically.

 

[ResearchinStuff]

Have a buddy who can shoot it?

 

[Maineiac]

I’m sure I could scrape one up if I had to. I think I’ll start by bedding the action and free floating the barrel, it seems easier.

 

[ResearchinStuff]

Those are always good steps. Lamp thread tends to work well for pillars too.

 

[Tikka300wsm]

How often are you cleaning the barrel? Doing anything between range trips? If you aren’t cleaning between trips then it sounds like you need to open up the barrel channel a little more.

 

[Maineiac]

while trying to figure this out I cleaned it periodically (with powder solvent, nylon brush and then patched it clean) sometimes waiting 5 shots between cleaning and sometimes I’d clean it after each shot trying to see if the status of the barrel would influence the POI. It did not have a detectable influence on POI. Dirty cold shot the same as clean cold. Dirty hot shot high and so did clean hot.

 

[Tikka300wsm]

How many shots do you normally go between barrel cleanings? The rifle groups fine once it’s warm?

 

[Maineiac]

I usually clean after each range session, they don’t typically go beyond 20 rounds, maybe never beyond 20 rounds I suppose. Yes, the rifle is tight and consistent once warm. I don’t think I’ll remember to compensate once the action starts. Being calm and cool is one thing remembering details about proper holdover based on barrel temp is beyond my limited ability.

 

[Tikka300wsm]

I’d clean the barrel less often and run an index card between the barrel and stock to see how well floated it is. Doesn’t sound like the scope is the issue here.

 

[Maineiac]

I haven’t seen anything on Pilar bedding before, is there an accuracy difference between it and glass bedding?

 

[Maineiac]

I’d clean the barrel less often and run an index card between the barrel and stock to see how well floated it is. Doesn’t sound like the scope is the issue here.

Barrel is not floated. Solid contact between barrel and stock on both sides and bottom. I’ve never had a clean rifle shoot poorly, though I’ve heard it. It did not appear as though cleaning influenced POI, I think my next step will be to float barrel and bed action.

 

[ResearchinStuff]

I haven’t seen anything on Pilar bedding before, is there an accuracy difference between it and glass bedding?

Pillars give you solid metal between the head of the action screws and the action itself. This allows you to torque those screws tighter without crushing the stock, eliminating potential movement. When I glass bed, I always add pillars too unless the stock already has them or an aluminum bedding block.

You're cleaning an absurd amount, this isn't a flintlock shooting black powder.

 

[morgaj1]

Pillars give you solid metal between the head of the action screws and the action itself. This allows you to torque those screws tighter without crushing the stock, eliminating potential movement. When I glass bed, I always add pillars too unless the stock already has them or an aluminum bedding block.

You're cleaning an absurd amount, this isn't a flintlock shooting black powder.

^^^This.


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[EdP]

It is common for a clean bore shot to have a different POI from subsequent shots, especially from a barrel that has been oiled after cleaning. Try not cleaning and see what happens. Also, for some rifles, removing any oil from a clean bore using rubbing alcohol on a few patches solves the issue.

Before heading out on a hunt, either local or distant, I clean the bore after my last range practice session. Then, before leaving, I shoot 2 or 3 shots and case the rifle for travel. I can do those "fouling shots" at home but they can be done anywhere safe. Just don't do them when checking zero after travel and have it look like your gun is off.

 

[Maineiac]

Pillars give you solid metal between the head of the action screws and the action itself. This allows you to torque those screws tighter without crushing the stock, eliminating potential movement. When I glass bed, I always add pillars too unless the stock already has them or an aluminum bedding block.

You're cleaning an absurd amount, this isn't a flintlock shooting black powder.

Adding metal pillars sounds smart and I appreciate the advice and explanation.
It doesn’t seem unreasonable to me. I clean my guns after a range session. I prefer not to leave them dirty. When I hunt I hunt with a clean barrel. I was trying to eliminate variables while searching for the cause of the consistent inaccuracy; if the gun shot different clean vs dirty cleaning it is required.

 

[EdP]

if the gun shot different clean vs dirty cleaning it is required.

A barrel will lose accuracy when badly fouled. At that point a good cleaning with focus on copper deposit removal is needed. Prior to that point cleaning is not really needed although I also prefer to clean more often and remove copper ahead of it becoming a problem. Cleaning after every range session of 20 shots or so is not needed. Minor fouling produces consistent conditions, the best accuracy, and a reliable POI. Your cleaning and shooting method is virtually guaranteed to give the POI shift you describe. You can spend a lot of time and money modifying your rifle and will likely still have the same problem if you don't change your method. Bedding and pillars will typically help a rifle shoot more accurately, but you are not describing an accuracy problem and would not expect one with a fine rifle like a Sako.

Maybe I will be surprised but I don't think you will find folks on here saying they hunt with a perfectly clean barrel. That might be a question to ask of the forum members.