Slow proof prefit?

[clark33]

Have a Terminus Apollo lite with a Proof CF 24" prefit, 7.5 twist. Took it out and ran some Hornady Match 147 and Berger 140 Elite hunter ammo through it. The 147 match averaged 2845 over 10 shots and the Berger 140 averaged 2820 over 10 shots. This is basically 6.5cm velocities, curious if anyone has experience a slow proof before? It's accurate so I am not to worried about it, and it should speed up a little with a few more rounds through it, but dang.

Chrono used was the new Garmin Xero C1

 

[Dmagna]

Have a Terminus Apollo lite with a Proof CF 24" prefit, 7.5 twist. Took it out and ran some Hornady Match 147 and Berger 140 Elite hunter ammo through it. The 147 match averaged 2845 over 10 shots and the Berger 140 averaged 2820 over 10 shots. This is basically 6.5cm velocities, curious if anyone has experience a slow proof before? It's accurate so I am not to worried about it, and it should speed up a little with a few more rounds through it, but dang.

Chrono used was the new Garmin Xero C1

Put a 100 though it and see what you get after.

 

[clark33]

Yea I'm working on it, I'm at 50 right now. She should speed up a little but I'm thinking at best I'll get close to 2875ish, maaaybeee scratch 2900 on the hornady match.

 

[Dmagna]

Yea I'm working on it, I'm at 50 right now. She should speed up a little but I'm thinking at best I'll get close to 2875ish, maaaybeee scratch 2900 on the hornady match.

What does the box say for factory speed?

 

[lancetkenyon]

I have had, and seen, a few slow Proof barrels.
I had a 26" 1:7.5" Proof on a 6.5SS, and replaced ot with a 26" 1:7.5" Bartlein. The brand new Bartlein ran 30fps faster than the fully broken in Proof with the exact same handloads.

 

[clark33]

What does the box say for factory speed?

Berger says 3,109 and is Hornady match is 2910.

Its running almost 300fps slower than advertised on the berger stuff.

 

[Sockeye66]

Any way you can verify the chrono with a known velocity from a different rifle/cartridge?

 

[clark33]

I did, I have a 21" 6 creed with a known avg velocity, the new garmin lined up with that avg today.

 

[Ckleeves]

I would try to run a few out of the same box/lot out of a different rifle and see. There are some real slow lots of 147's floating around out there. The Berger seems off I haven't heard or seen any slow lots from them.

 

[Gregg C]

Tagging in. I have no experience with Proof Research, but I did have a " slow" barrel on a 33XC. It was accurate, but the performance wasn't there. After 500 rounds, I gave up and had it replaced. The new barrel showed me 3200fps with a 300gr SMK yesterday in a pressure ladder. I'm much happier with it.

 

[highdrum]

I've had proof prefits that have(had) notably undersized chambers showing pressure signs early on brass. One was a prc, others 65 and 6mm creeds. I have some jgs saami reamers on hand, and cleaned them up. After reaming them, I had adequate neck clearance on the 2x 6cm blanks, and proper body dimensions on the 65cm. The prc was opened with AW2 reamer at 0.200 line. All was better after the clean up, running as expected velocity without any psi signs.

Proof runs their prefit reamers way too long wearing them down, or they buy in bulk off PTG's ebay page, possible combo of both.

 

[vancewalker007]

I've had proof prefits that have(had) notably undersized chambers showing pressure signs early on brass. One was a prc, others 65 and 6mm creeds. I have some jgs saami reamers on hand, and cleaned them up. After reaming them, I had adequate neck clearance on the 2x 6cm blanks, and proper body dimensions on the 65cm. The prc was opened with AW2 reamer at 0.200 line. All was better after the clean up, running as expected velocity without any psi signs.

Proof runs their prefit reamers way too long wearing them down, or they buy in bulk off PTG's ebay page, possible combo of both.

Do you think its better to buy a raw barrel and have a Smith chamber it or start with a prefit and clean it up?

 

[highdrum]

Do you think its better to buy a raw barrel and have a Smith chamber it or start with a prefit and clean it up?

If money is no concern, buy a blank and have good smith chamber it, absolutely. I got these proofs a few years back, and CHEAP. Prob cuz the original owners were having issues with hand loads. This was just a quick fix. I will be buying straight steel and fluting from now on.

 

[Jeffrey Van Zandt]

Have a Terminus Apollo lite with a Proof CF 24" prefit, 7.5 twist. Took it out and ran some Hornady Match 147 and Berger 140 Elite hunter ammo through it. The 147 match averaged 2845 over 10 shots and the Berger 140 averaged 2820 over 10 shots. This is basically 6.5cm velocities, curious if anyone has experience a slow proof before? It's accurate so I am not to worried about it, and it should speed up a little with a few more rounds through it, but dang.

Chrono used was the new Garmin Xero C1

may speed up around 75-100 rounds or till your barrel gets some copper build up in it. if you are building a rifle built for a specific bullet say the 156 berger then have a smith do the chamber other ways just do a prefit proof