Got bored, built another Finnish TKIV85 Sniper. Now with Shroud Results!

[buffalowinter]

As you might have seen from my previous post here, I am building a Finnish TKIV 85 Sniper rifle. Well, the Toro bedding block is having some problems and has been sitting in someone's shop or almost a year and half. On my way to building this, I actually acquired an additional stock that doesn't have the adjustable cheek piece. This was the "target" model but also saw service in the Finnish Army as a sniper rile. I had an additional Toro block, which attaches between the barrel and receiver and is the only part that touches the stock. I acquired a Finnish M28/76 from jwsubMOA here on the Hide at a bargain price because it had a couple of problems. I thought I would try a different method of attaching the Toro block to the barreled action than what was normally done. I bedded the Toro block into the stock so that everything was free floating except for the block itself. Since this wasn't going to be a clone, I went ahead and used a "Rock Solid" picatinnny rail scope mount. I mounted a vintage 10x56 Schmidt and Bender scope to complete "The Look". I used a Timney 3 lb fixed target trigger, which is OK, but I'm not sure is any better than the M28/76 trigger, and I may go back to a tuned original trigger. The barreled action is a stock M28/76 save for the TKIV bolt knob I put on. I loaded some rounds using Lapua brass, Lapua D166 .310 200g bullets, Federal Match Magnum primers, and Vhitavouri N140 powder. I couldn't be happier with the results. Best 5 shot group was around .5 moa, with another 5 shot group around .9 moa. I shot a 10 shot group with 7 shots in a ragged .7 moa group. I pulled the first and last shot which opened up the group. The 10x S&B is a nice scope but is 60 year old technology and a pretty severe handicap for old eyes. Next, I'm going to put a carbon fiber barrel shroud on it to see how it affects accuracy.

Toro bedding block

 

[Forgetful Coyote]

As you might have seen from my previous post here, I am building a Finnish TKIV 85 Sniper rifle. Well, the Toro bedding block is having some problems and has been sitting in someone's shop or almost a year and half. On my way to building this, I actually acquired an additional stock that doesn't have the adjustable cheek piece. This was the "target" model but also saw service in the Finnish Army as a sniper rile. I had an additional Toro block, which attaches between the barrel and receiver and is the only part that touches the stock. I acquired a Finnish M28/76 from jwsubMOA here on the Hide at a bargain price because it had a couple of problems. I thought I would try a different method of attaching the Toro block to the barreled action than what was normally done. I bedded the Toro block into the stock so that everything was free floating except for the block itself. Since this wasn't going to be a clone, I went ahead and used a "Rock Solid" picatinnny rail scope mount. I mounted a vintage 10x56 Schmidt and Bender scope to complete "The Look". I used a Timney 3 lb fixed target trigger, which is OK, but I'm not sure is any better than the M28/76 trigger, and I may go back to a tuned original trigger. The barreled action is a stock M28/76 save for the TKIV bolt knob I put on. I loaded some rounds using Lapua brass, Lapua D166 .310 200g bullets, Federal Match Magnum primers, and Vhitavouri N140 powder. I couldn't be happier with the results. Best 5 shot group was around .5 moa, with another 5 shot group around .9 moa. I shot a 10 shot group with 7 shots in a ragged .7 moa group. I pulled the first and last shot which opened up the group. The 10x S&B is a nice scope but is 60 year old technology and a pretty severe handicap for old eyes. Next, I'm going to put a carbon fiber barrel shroud on it to see how it affects accuracy.
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Toro bedding block
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Details on carbon fiber barrel shroud?

 

[buffalowinter]

Just an experiment, partly cosmetic to hide the ugly military contour barrel. I've shrouded two other pencil barrels by using acra-glas between the barrel and shroud and that seemed to have an adverse effect on accuracy. For this one I have a two mm thick shroud that is a friction fit at the base of the barrel under the Toro block and fastens at the muzzle with a set screw in an aluminum fitting. The shroud free-floats from the Toro block to the muzzle. I'm going to drill some holes on the underside of the shroud that will be concealed by the stock and should aid cooling. It will be interesting to see how this effects barrel harmonics.

Failed experiment with barrel shroud on .300 win mag semi auto I built

 

[buffalowinter]

Shroud done

 

[Random Guy]

You built a 300 Win Mag semi-auto as an experiment?!
You got some skills.

 

[buffalowinter]

Yes, the .300 win mag was based on a Browning and worked well. The carbon fiber shroud adversely affected accuracy.

 

[buffalowinter]

Barrel shroud really seems to have positively affected barrel harmonics/stiffness/barrel gods. Not too sure how the shroud improved accuracy, but below are some groups I just shot. All are 5 shots at 100yds. Note that groups are measured outer edge to outer edge so you have to subtract .310 to get center to center size. That makes the best group .22 MOA. Largest groups were under .75 MOA. I did put a Vortex 24x scope on to better get a better idea of accuracy as opposed to my ability to see.

 

[ShooterwithNoName]

That's awesome buffalowinter, I have a soft spot for these rifles. Im pretty impressed with the accuracy of that 28/76 barreled action. They are really well made rifles.

I picked up a 28/76 stock from you a while back. Since you have this thread going I thought I would bump it with a pic of mine with the stock I got from you...

I'm going to try this barrel out before pulling it to replace with a .308 bore barrel. The barreled action is a 1944 M39 SA marked Sako. The bore appears to be in excellent condition. I still haven't finished scrubbing the cosmo or whatever out of the barrel.

Im still building it, I'm going to probably fabricate a replica bolt body and handle. I haven't had any luck with finding a 28/76 bolt body, not many floating around. I picked up an early Ivshesk and Sestroyesk bolt head. The receiver was originally a 1905 Ivshesk so I'm trying to keep the bolt head the same era and find one that headspaces.

Anyway, great work on your TKIV build. I did score an original M28 trigger and matching sear. Looking forward to trying it out because I've heard they are pretty good.