Happy with PROOF Carbon 338

[Magnum_Willys]

Have seen mixed reviews of the Proof Carbon barrels but I think they are getting their act together.  This 30" 338 Lapua barrel is a consistent shooter and I'm pushing it pretty well - 66k psi according to quickload with Lapua brass.

The barrel did take a looong time to settle down - about 150 rounds before speed settled down - 75fps + over initial.

My HCA didn't take nearly that long to settle down but may have been the different reamer.  The reamer on this new one maybe was worn or out of spec as my throat is snug on the 300 gr Berger.    Actually polished the throat before the lands with JB's to make sure bullet didn't pull out when unloading.     But I've gotten zero throat erosion in the first 250 rounds which has got to be due to tight bore.

Can shoot 6" groups at 1000 when wind is down,  today with variable wind it held all 6 shots at waterline at 1016 yards - about 1" vertical after initial sighter.

[jasnt]

Looks good

[Bango skank]

Wow, good shootin.  Im waiting on one of the new savage ultralites with the proof barrel to arrive.  Im sure it will suit my purposes of 5-300 yard shooting.

[Dan-o]

I'm no distance shooter, but that is super impressive to me.

[Bushcraft]

Nice consistent velocity drop you’ve got there.

The 150 does seem a little high for barrel speedup on a larger diameter bore.

I use the LabRadar to keep tabs on things but on the NRL/PRS comp guns I don’t even bother using them until there’s 150-200 rounds down the pipe before settling down on a load. Even then the throats erode a significant amount over the course of a weekend match. Then again, we run them a little harder than hunting rifles. 

Question: What does a tight bore have to do with throat erosion? I haven’t heard that before.  Also, what action are you using?

[Magnum_Willys]

Stiller Tac 338.   I read recently that a tight bore reduces blowby around the bullet and reduces erosion.  Did’t know if true but beginning to think so.  Read .0005 max over bullet diameter suggested.   Mine must be same size as bullet.  Told Smith I thought his reamer was under cutting due to getting dull but he didnt think so.  Was PTG reamer and I read sometimes their specs vary - not sure how you hold specs with different barrel mfg's and hardnesses and different lathe operators anyway.

Speeds were 2882-2991 so es of 9. 

My new .02 powder scale makes a difference for sure.

[hogslayer]

There is usually .007-.008” between groove and bore diameter. A tight barrel is usually groove diameter that increases resistance on the bullet and cause earlier pressure.  Krieger barrels are known for being tight.  Broughton’s are not.  You might be taking about the freebore diameter of the reamer.   In larger cases, .001 over bullet diameter is usually desired.  Minimum spec is .0005.  The FB or the reamer is what usually gets warn first.   It’s pretty easy to see if the FB is tight by looking through a bore scope. You can see residual land material on the FB area.  I am currently testing some different groove diameters in barrels.  Initial testing in 6 BRA showed 80 FPS velocity gain with small changes to diameter. Next up is a 338 Edge barrel.

[Bushcraft]

Initial testing in 6 BRA showed 80 FPS velocity gain with small changes to diameter. Next up is a 338 Edge barrel.

Interesting!  Keep us posted.

[Magnum_Willys]

Yep freebore area - I was surprised it was tight but could see no signs of uncut lands. ?

Still trying to  get a handle on barrel speedup.   Would think breakn = less friction but friction reducing coatings lower speed.   
More pressure = more speed but how does mire shots = more pressure if cleaning?   Hmmm

[hogslayer]

If your running RL33, I would be cleaning every 30-50 rounds. 

[Magnum_Willys]

If your running RL33, I would be cleaning every 30-50 rounds.

Good advice, I’m having good results cleaning every trip which is 20-30 rounds.

[NWShooter]

That horizontal looks a little spread to be wind. Could be parallax, Cheek hold or trigger.

[Magnum_Willys]

That horizontal looks a little spread to be wind. Could be parallax, Cheek hold or trigger.

  Some mirage in there too.  can watch the cross hairs dance a bit.  I don't worry about horizontal tho as long as I'm good vertically since just 3 mph wind change is a foot difference horizontally.  I can tell when my form needs work - when it gets tough to spot the shots with a 10# rifle shooting  300 grainers at 2900. 

[NWShooter]

Mirage can be a challenge when it comes to vertical. If you are dealing with mirage horizontally at that distance. The windage knob has been cranked a bunch. I’m solid 24/7 with a 8 lbs rifle shooting 215’s @ 2950 all day long(1-9 Proof CF/Suppressed). Proper throat geometry and common sense will get you 1/3 MOA out to as far as a 215 is capable and they deliver way beyond the basic minion mind set.

[TRD1911]

Love my two proof carbon barrels. One in 6.5cm and another in 300 Norma Mag. The fact that they were both spun up by Sawtooth Rifles didnt hurt either. Great shooters

[Magnum_Willys]

Looks like winds will be very still saturday so will see if I can squeeze a 5” group out of it at 1000 yards.
Idk this new batch of Bergers is .007 different jump so that could change things.   

[jasnt]

Looks like winds will be very still saturday so will see if I can squeeze a 5” group out of it at 1000 yards.
Idk this new batch of Bergers is .007 different jump so that could change things.   

hopefully the new batch does better

[NWShooter]

If you are shooting the 300gr Hybrid. Chances are .007 won’t make much of a difference. Most Hybrids I have shot like as much as .040 off the lands as compared to the original standard 300gr VLD. The original .338 VLD I use to “Jam” .015 into the land to get top accuracy, the Hybrids I shoot like .040 off. Same story for the .300 Win Mag and the 215’s. H-1000 is the top choice. Retumbo as a desperate second if H-1000 is scarce. Federal Match 215’s across the board.

[jasnt]

Can you see 1000 today?  I can barely see my 500 yard plate today

[Magnum_Willys]

I'm looking at 0 mph wind, but they closed my shooting area  understandable tho.    Not sure I could see 1000 yards anyway......

[TheArmoredShop]

That horizontal looks a little spread to be wind. Could be parallax, Cheek hold or trigger.

Coriolis effect!

[jasnt]

That horizontal looks a little spread to be wind. Could be parallax, Cheek hold or trigger.

Coriolis effect!

coriolis can affect point of impact but will not widen group size.  At 1000 yards Coriolanus is about one click but it’s also very consistent and will not effect group size only poi.  Wind or trigger or position can.