30 BR struggle is real

[Doublejake]

I was shooting a Hart 18 twist HV. The gun was a Hammer with LT 30 34.8 gr. Any load would have a 7-10 FPS extreme spread.

Now a new barrel Bartlien 17 Twist LV.
The old load for other barrel was way too hot.
Currently at 34 gr.
I have done charge weight testing with LT30 and N130. Terrible FPS spreads. Decent until I get one high or low.
I have replaced the spring with a 24lb wolf that Kelby says they use. Spring was chamfered on each side.
Using brass from other barrel. Anneal every time.
I also did a 200 yard seating test with the 34gr.
Any thoughts about what is going on is very welcomed.
Larger sample sizes on all charge weights are averaging 50FPS spreads.

 

[AckleymanII]

Have you examined the bore when clean with a bore scope?

 

[Doublejake]

Yes! I checked barrel with scope after cleaning. I bring it back to bare metal. I run dry patches till they are dry. I also have noticed that it takes 8-10 shots after cleaning to settle in when any other barrel was 1-3 shots.

 

[Charwell]

Try a .324 bushing.

 

[LHSmith]

I tune to the target results. I have never gave ES a consideration in my 24 years of SR BR competition.

 

[AckleymanII]

Quote: "Yes! I checked barrel with scope after cleaning. I bring it back to bare metal. I run dry patches till they are dry. I also have noticed that it takes 8-10 shots after cleaning to settle in when any other barrel was 1-3 shots."

There is a big lesson here!

 

[Doublejake]

Try a .324 bushing.

I have. Same FPS issue

 

[Doublejake]

Quote: "Yes! I checked barrel with scope after cleaning. I bring it back to bare metal. I run dry patches till they are dry. I also have noticed that it takes 8-10 shots after cleaning to settle in when any other barrel was 1-3 shots."

There is a big lesson here!

Which is?

 

[Doublejake]

I tune to the target results. I have never gave ES a consideration in my 24 years of SR BR competition.

My targets clearly show the higher and lower impacts with the FPS spread.

 

[boltfluter]

I tune to the target results. I have never gave ES a consideration in my 24 years of SR BR competition.

This. Possibly the new barrel is still speeding up and not settled in yet. Been there and done that! No fun. How many rounds down the new tube?
Paul

 

[X-Caveman]

If it were me (and I hadn't already), I would:

• Check neck clearance. Maybe tighter neck on new chamber?
• Check all fasteners
• Try a different primer (seating to slight crush)
• Stop annealing
• Try another scope
• Clean less rigorously

 

[Doublejake]

This. Possibly the new barrel is still speeding up and not settled in yet. Been there and done that! No fun. How many rounds down the new tube?
Paul

Over 400

 

[Doublejake]

If it were me (and I hadn't already), I would:

• Check neck clearance. Maybe tighter neck on new chamber?
• Check all fasteners
• Try a different primer (seating to slight crush)
• Stop annealing
• Try another scope
• Clean less rigorously

Neck clearance with the new barrel and loaded round is also around 2th from a fired case

 

[Doublejake]

Always crush primer in deep as they will go. Scope was swapped from a golden eagle to a March 48x

 

[Doublejake]

Brass carbon patterns are a complete circle at the tip of the neck, or lug bolt pattern on the lower charge weights

 

[boltfluter]

Over 400

Well that's not good. Personally I would let my target dictate how I moved forward and put the chronograph away. Try cleaning less, as in not to bare metal. Do away with annealing as a test. Carbon in the case necks is your friend. Think lubrication. I.e. lower extreme spreads. Just a few things to ponder. Good luck and keep us posted.
Paul

 

[sqrlgtr]

Just a thought maybe check trim length. If I read right you are using brass fired from old chamber, New chamber may be alot shorter???. Should be able to tell how much clearance you have with the bore scope. I am also using 324 bushing and jam bullet 20/30 thou. Best of luck....

 

[LHSmith]

I always bought new brass for a new barrel and dedicated it solely to that specific barrel. That was before the current supply chain problems, but it eliminated a lot of variables that could cause issues and perhaps wasting components and barrel life trying to solve those problems.

 

[AlNyhus]

Let's go a step at a time.
- What does the neck O.D. measure when checked with a .0001 micrometer over the pressure ring of the bullet when seated?

 

[Bill Norris]

Neck clearance with the new barrel and loaded round is also around 2th from a fired case

You might try a tad more clearance as well as moving down in bushing size. Some barrels simply want more neck tension.