Proof PXT testing with Alex Wheeler

HellsCanyon · Jun 12, 2026

Alex Wheeler said:
They were slower with the same load or slower when pressured out? I should have been more specific with my post. The bigger groove let me add more powder and get more speed before hitting pressure signs.

I have seen in the last 18 months 4 barrels that shot boxed hornady ammo 40-50fps faster with grooves that measure .0005-.0008" over nominal.

We actually discovered this by taking barrels we were about to reject because they were "too big". Turns out they shot factory ammo better and faster…..

There's a definite sweet spot for speed and accuracy. Too tight is way worse than too loose, neither are great.

Mike

HellsCanyon · Jun 12, 2026

Justice1327 said:
Will yours use ECM for rifling?

howco said:
@ Mike HCA...... I see this post and I'm hours late....literally. I have two of your fast twist for caliber carbon barrels that just hammer. I went and ordered a pre fit barrel/pxt for a Tikka laying around. I figured I'd give one a try instead of being a naysayer.

No worries man get us on the next one

Alex Wheeler · Jun 12, 2026

My guess is if they shot the factory faster those bullets were on the fat side. When I first started playing with grooves I expected to have to add powder to get my velocity back. But surprisingly they shot the same speed. However I could run them up higher than I could in a standard groove. Most BR bullets are fat but they don't have a lot of bearing surface. Once I got to .0008" over I saw accuracy loss. Still capable of .3's but no longer .1"s. Thats a pretty big loss. For a while I ordered all my barrels at .2435" and had a lot of very good shooters.

liv4thehunt · Jun 12, 2026

This is the first PXT that I put together back in March. It's a 6.5 creedmoor for NRL hunter. This was one of his first groups on paper, with ammo loaded for a different rifle. 5 days later my customer won his class.

Rhovee · Jun 12, 2026

I went out and shot 195's @ .055 off last night with the three powders, N570, N568, Retumbo. After looking at previous notes and 26" barrels, 79.5-80 grains of N570 is 3050, Retumbo is 78.5-79. I have a 22" barrel so anticipating about 80-100 FPS slower. I am expecting 2950 ish with this barrel. The barrel has 50 rounds on it and the throat has not moved. At this point, I will continue with N570. Tonight/tomorrow I will do a seating depth test with 83 grains of N570.

N570:
79.5-2790
80.5-2830
81.5- 2870
82.5-2930

Retumbo
78-2780
79-2830
80-2840
81-2890
82-2922

N568
79-2710
80-2710
81-2750
82-2760

Lenwood901 · Jun 12, 2026

Any pressure yet and how was the groups so far

Huntnful · Jun 12, 2026

Rhovee said:
I went out and shot 195's @ .055 off last night with the three powders, N570, N568, Retumbo. After looking at previous notes and 26" barrels, 79.5-80 grains of N570 is 3050, Retumbo is 78.5-79. I have a 22" barrel so anticipating about 80-100 FPS slower. I am expecting 2950 ish with this barrel. The barrel has 50 rounds on it and the throat has not moved. At this point, I will continue with N570. Tonight/tomorrow I will do a seating depth test with 83 grains of N570.

N570:
79.5-2790
80.5-2830
81.5- 2870
82.5-2930

Retumbo
78-2780
79-2830
80-2840
81-2890
82-2922

N568
79-2710
80-2710
81-2750
82-2760

Any pressure yet? So far it's just taking more powder, for less speed. Unless you can keep adding powder to eventually overcome the pressure/velocity loss, I'm not intrigued at all at the moment. Regular twist barrels shoot lights out, so precision is not the deciding factor here.

I'm curious about increased speed, and maybe increased barrel life as well.

bigbulls · Jun 12, 2026

In 50 more rounds you should see another 25-50 fps barrel speeding up unless these new ones don't do that. The last 8 Proof barrels of mine increased right at a 100 fps from start to about 120 rounds.

bigbulls · Jun 12, 2026

Have you found pressure yet?

Rhovee · Jun 12, 2026

I have not found pressure yet. I will tonight. With all formed brass we should have better data.

Huntnful · Jun 12, 2026

Rhovee said:
I have not found pressure yet. I will tonight. With all formed brass we should have better data.

Good point there. Finding pressure on virgin brass wouldn't have been an accurate baseline anyways. Thank you for the testing and sharing you're doing for us!

HSmithTX · Jun 12, 2026

Yes, thank you for doing this, not too many would drop over $2K to find out and share all of the info.

greene0331 · Jun 12, 2026

Huntnful said:
"I'm not intrigued at all at the moment. Regular twist barrels shoot lights out, so precision is not the deciding factor here."

"I'm curious about increased speed, and maybe increased barrel life as well."

Same. So far I haven't seen anything that would cause me to pick one of these up for my newest build. I'm still open to the idea and look forward to seeing more real world results, thanks to the testers in the thread!

COL127 · Jun 12, 2026

Tag in to keep up

Proof PXT testing with Alex Wheeler

HellsCanyon

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HellsCanyon

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Alex Wheeler

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liv4thehunt

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Rhovee

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Lenwood901

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Huntnful

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bigbulls

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bigbulls

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Rhovee

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Huntnful

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HSmithTX

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greene0331

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COL127

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