Bolt lug contact and amount of free float

[ofbandg]

In a rifle that heats up quickly I find a business card gap in the float is minimal. I often put a two business card gap. It may not look as pretty but my pretty rifles stay in the safe. More air circulating around the barrel also helps with cool down. The other issue is bedding around the recoil lug. I have two Tikkas and they are touchy when it comes to bedding the lug, but it does help. Finally, I'm not a fan of their scope mounting system. Everything has to be torqued to max and stay that way, which isn't always easy. When it does all comes together they are capable of excellent accuracy. Good luck with your project.

 

[RYEWSKY25284]

I have two questions for everyone.

I was recently reading something about checking bolt lug contact for squareness. The instructions were to put sharpie on the rear face of the boot lugs, then cycle the bolt 10 or so times. The amount of sharpie worn off each lug should be the same.

I did this and the picture shows each lug. This is a Tikka bolt. Does this look good enough?

The other question is, how much free float do I really need on my foreend? I have a .30-06 t3x superlite that's bedded into a Boyd's laminate prairie Hunter stock, with torque set to 65in/lbs. I have a little less than 1/16" free float. Is this enough? Do I need more to be sure the barrel isn't hitting the foreend during recoil?

Thanks!

lugs look fine.

 

[Tac-O]

Lugs appear fine.
Now , as to how much free float. Back in the day, when we would question if more free float was needed , the answer was achieved by taking the barreled action out of the stock, applying lipstick appropriated from our female better half to the portion of the barrel encased by the forearm. Then carefully putting the rifle back together so as not to bump the barrel in the barrel channel leaving an unwanted mark.
Shoot the rifle !
Carefully take barreled action from the stock. If there are any lipstick marks in the barrel channel left by vibrations of that "painted hussy barrel", dress 'em out. Repeat "glammin' up the barrel" and shooting until you are satisfied you have enough free float.
Now a days , I will use Jarrows Inletting Ink. Jarrows comes in black n gold, and is more pliable/softer than the lipstick so more care is needed when assembling/reassembling.

I've been planning to do that with some hi spot blue I have!!

 

[OG10]

Hardest part with mine, if I am the weak link, is getting it to recoil same way every time. I should have hit the easy button and gotten my stainless Tikka in a 6.5 creedmoor instead
[/QUOTE] thats funny but true

 

[257RobertsMan]

Here's today's. Not bad, but it looks like a slight POI shift from group 1 to 2. I'm not sure what caused it, but I'm thinking cheek pressure or shoulder pressure.

Looking at group 1, it appears that you broke your shot at different points during your breathing cycle, thus vertical stringing. Different poi's in the horizontal plane is usually from trigger control errors or wind.

This might not be the problem, however watch your retical as you breathe and see if your scope moves, try to break your shot at the bottom (respiratory pause) of your breathing cycle, don't hold your breath.

 

[340PR]

My $0.02. I have two T3x, one purchased about 12 mo after the other, both in 6.5CM. T1 was .5MOA or less, out of the box, using factory ammo (Norma match). With load development, was consistently .375MOA or better, depending on the shooter. Ran over 3000 rounds through T1, and won a 600yd target match the last time I shot it stock. What I noticed was that the hammer forged barrel was much slower in muzzle velocity than other rifles (2670 vs 2720) same load, bullet weight etc.. Also, as the round count went up, the MV went down (at 3k rounds, 2620). cleaning didn't seem to matter much (tried several intervals and levels). T2 was a .5 MOA rifle out of the box (on a good day). No matter what I did, I could not get it to shoot like T1. FYI. the muzzle velocity issue was the same as T1.
Put a Broughton 5R barrel on T1, and noticed a substantial increase in MV (2820 with same load). Won the first match I shot this year, with 160 rounds total on the barrel. The amazing thing to me was that the vertical spread was 0.100" over 4/5 round targets. Again, a 600yd match, with a 2.234" aggregate.
NOTES:
1. both rifles are free floating (factory).
2. I bump the shoulders back to "0", meaning that when the round is chambered, I can feel the shoulder seat as the bolt locks.
3. I run an "off barrel" V3, and record environmentals on all sessions except matches.
4. I have done a LOT of testing with case volume vs. load accuracy, etc. and found that ES is not the determining factor to accuracy (within reason).
5. I noticed that Forged barrels took longer to warm up than the Boughton (all within 1.5" @ 100 yds). factory CCB 1st impact is upper left, and strings down to center over 6-8 rounds. Broughton CCB is just low and left, and centers in 3-5 rounds.

Finally, to answer your question, both Tikkas show equal bolt wear on the lugs, AND they are smoooth...
hope this helps