The new 33XC & 37XC cartridges designed by David Tubb

[babyguppy]

33xc barrel question. I've got a line on a 1:9.3 twist 30" finish length or a 1:8 twist 28" finish length. I want to primarily run solids, something like the CE 275 or 300 gr lazers. This is going to be for 2400 and in. I'd like to get as much velocity as I can, do I want to scrap both of these and look for a longer barrel? CE lists the minimum twist rate for the 300 at 1:8.5.

I'm holding out for a 1:8 (which will still run my 300 bergers) for solids, with at least 32". IMO, I think you'll want at least 30" in 1:8 twist for your solids.
I was thinking to myself; self, you can always cut a 36" barrel down, but you can't weld it on.

 

[ForgeValley]

I'm holding out for a 1:8 (which will still run my 300 bergers) for solids, with at least 32". IMO, I think you'll want at least 30" in 1:8 twist for your solids.
I was thinking to myself; self, you can always cut a 36" barrel down, but you can't weld it on.

LOL, yes, no welding. I was thinking I really wanted to be closer to 32", but this is what a couple of guys had in stock so I was looking for the instant gratification. Any idea where I can find a really long 1:8 blank?

 

[JB.IC]

For solids up to 300gn, 8 twist is your best bet. 30” is fine. You’re splitting hairs over 2”: 28 vs 30”. However, if you favor slower powders like H50BMG or RL50, then you need some barrel length to get a complete powder burn. 30” is what I favor in that regard. Guys are getting good speeds around the length and 30” seems to be a common choice.

 

[babyguppy]

LOL, yes, no welding. I was thinking I really wanted to be closer to 32", but this is what a couple of guys had in stock so I was looking for the instant gratification. Any idea where I can find a really long 1:8 blank?

worth the wait

Home | Bartlein Barrels

www.bartleinbarrels.com

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[BCX]

Personally I would go w a 30 inch min 1-7.5 twist. Bartlein modBB

 

[ForgeValley]

worth the wait

Home | Bartlein Barrels

www.bartleinbarrels.com

linky

Yeesh. I was hoping to have it before 2023. . But yeah, I love Bartlein barrels.

 

[BCX]

worth the wait

Home | Bartlein Barrels

www.bartleinbarrels.com

linky

I may have a connection for a 1-8. I will send you a PM, hang tight!

 

[ForgeValley]

For solids up to 300gn, 8 twist is your best bet. 30” is fine. You’re splitting hairs over 2”: 28 vs 30”. However, if you favor slower powders like H50BMG or RL50, then you need some barrel length to get a complete powder burn. 30” is what I favor in that regard. Guys are getting good speeds around the length and 30” seems to be a common choice.

Probably going with H50 because I can find it and actually have quite a bit for the Cheytac.

 

[badassgunworks]

33xc barrel question. I've got a line on a 1:9.3 twist 30" finish length or a 1:8 twist 28" finish length. I want to primarily run solids, something like the CE 275 or 300 gr lazers. This is going to be for 2400 and in. I'd like to get as much velocity as I can, do I want to scrap both of these and look for a longer barrel? CE lists the minimum twist rate for the 300 at 1:8.5.

Don't purchase a minimum twist rate barrel purchase one with fast enough twist that you can stabilize anything that you plan on shooting i would consider 32" minimum for the 33xc

 

[Swatdude1]

Personally I would go w a 30 inch min 1-7.5 twist. Bartlein modBB

I went with the 1:8 Mod BB finished 30" and it shoots lights out with solids. Only pushing 275gn at 3180fps but have no fire cracking after 100 rounds. Chase did tell me a 34" was probably needed to burn up all the H50BMG but the 30" is even getting a little long IMO for an MRAD. Now if I was doing a 41XC I'd probably go 36" on a dedicated build.

 

[BCX]

Stay tuned,,,, little Canadian and English teaser

I have high expectations out of this ModBB. Should have it next week.,

 

[TreyMeTrey]

If you have ever seen him shoot ELR, you will appreciate this concept very quickly!



View attachment 6935534

He shoots with a Magneto Speed on his rifle so he can constantly measure his Muzzle Velocity. At ELR ranges muzzle velocity is a total make or break issue.

Everyone is chasing the pot of gold at the end of the rainbow! Interestingly David is going about it in a different manner. Rifle design, cartridge design, and techniques.

It is very cool to see the birth and evolution of a new shooting capability. Give it a couple of years, and shooting at 2,000 yards will start to look a lot more like shooting at 1,000 yards.

It is there now.

 

[stefan73]

It is there now.

That is interesting how he has it attached to the chassis and not the barrel.

 

[babyguppy]

That is interesting how he has it attached to the chassis and not the barrel.

Yuupers, you don't have to worry about the chrono effecting you POI.
I find it odd, he has it off to the side, where the muzzle blasts hits VS underneath, away from the blast.
Edit - It's also nice, if you load 50 rounds, you can measure all 50 over an extended period (just don't clear it) to watch (as in my case) your SD grow making sure the ambient temp is about the same when you shoot. Or clock what the FPS is at 80, 90, 100, 110 degrees and how ambient effects FPS. I need to start logging it better.

 

[stefan73]

Yuupers, you don't have to worry about the chrono effecting you POI.
I find it odd, he has it off to the side, where the muzzle blasts hits VS underneath, away from the blast.

Same here. This is the first time I have seen someone mount one like that and it totally makes sense. I haven't bought one because of the POI shift, but to fab up something like this where you can work load data without worry about POI shift is a win.

 

[6.5SH]

Yuupers, you don't have to worry about the chrono effecting you POI.
I find it odd, he has it off to the side, where the muzzle blasts hits VS underneath, away from the blast.
Edit - It's also nice, if you load 50 rounds, you can measure all 50 over an extended period (just don't clear it) to watch (as in my case) your SD grow making sure the ambient temp is about the same when you shoot. Or clock what the FPS is at 80, 90, 100, 110 degrees and how ambient effects FPS. I need to start logging it better.

His brake has some odd angles, it is out of the way for the most part. Given where his bipod is don't think he has room on the bottom unless he makes a longer handguard.

 

[6.5SH]

The 2nd gen has more adjustment and can get under it even when mounted to the side.

 

[BCX]

One step closer

 

[babyguppy]

One step closerView attachment 7929292

who manufactures the 3? The middle one looks like there's a ring on it.

 

[ForgeValley]

One step closerView attachment 7929292

Me too... just got my barrel today.

 

[BCX]

who manufactures the 3? The middle one looks like there's a ring on it.

As George Gardner likes to say it’s Secret Squirrel Shit

 

[BCX]

Me too... just got my barrel today.

View attachment 7929411

I have had my barrel for about a month, just been to busy w work. Hopefully this weekend I can get out and start pressure testing!

 

[BCX]

who manufactures the 3? The middle one looks like there's a ring on it.

Badlands, Warner, Badlands!

 

[Swatdude1]

Badlands, Warner, Badlands!

The Warner has the Tubb Nosering option for smoother transonic transition. As a side note, I would not allow my daughter to get a nosering.

 

[babyguppy]

The Warner has the Tubb Nosering option for smoother transonic transition. As a side note, I would not allow my daughter to get a nosering.

that's why I asked, I thought it looked like it had one. Thank you!!

 

[BCX]

Yes the Warner Flatline has the Tubb ring.

 

[BCX]

Bartlein modBB 1-7.5 finished at 30 inch plus Cadex brake. She should run faster than my 338 LM Ack Impr…

 

[BCX]

Has anyone else experienced Badlands pressuring out earlier than the Warners? I know the bearing surface is longer on the Badlands.

 

[badassgunworks]

Has anyone else experienced Badlands pressuring out earlier than the Warners? I know the bearing surface is longer on the Badlands.

Run a little bit longer jump it should solve the problem . Longer bearing surface will increase pressure much more so than any extra weight will

 

[Geno C.]

You able to measure your bullets diameter?

 

[BCX]

Yes, I will take some measurements and compare to the Warner Flatlines..

 

[Dave62677]

View attachment 7929544
Bartlein modBB 1-7.5 finished at 30 inch plus Cadex brake. She should run faster than my 338 LM Ack Impr…

Who spun your barrel? Thanks

 

[BCX]

Fritz @ Black Canyon Customs

 

[BCX]

Caution! I know there’s no replacement for displacement! Lost .185 of throat erosion w N570 and solids.. 117 rounds down the tube w a modBB barrel. Time to switch up powders and rework a load. RL33/H50 to slow down throat erosion.

 

[Geno C.]

H50
Is what’s up

 

[ForgeValley]

I had a jug of 570 and a jug of h50 out. Sounds like its good I went with the h50.

First load workup session, this was 122 grains h50 with 300 grain cebs. Think it liked this well enough to do a little more work at 122.

 

[BCX]

H50
Is what’s up

Geno I know I was warned, I had it in the cart multiple times but backed out. My supply room is over ran . Guess I will be adding H50 to my collection. This works out for the best I guess. Rather keep all the N570 for my other cartridges w a smaller appetite

 

[BCX]

ForgeValley let me know how much throat you lose around 100-120 shots!

 

[ForgeValley]

ForgeValley let me know how much throat you lose around 100-120 shots!

Will do. Have a match mid next month that should put me over 100.

 

[Dave62677]

Caution! I know there’s no replacement for displacement! Lost .185 of throat erosion w N570 and solids.. 117 rounds down the tube w a modBB barrel. Time to switch up powders and rework a load. RL33/H50 to slow down throat erosion.

U gotta pay to play , H50bmg is on sales at Brownells.

 

[BCX]

I know man, there is no free lunch. 16lbs of H50 ordered. Thank god hunting season starts otherwise this barrel would be smoked w load development

 

[Dave62677]

I’m at 126gr H50bmg with 285warners and 300bergers. Both traveling at 3150fps. I bet my 30” barrel is slower than you guys

 

[BCX]

I had 2 good loads running N570 at 3190-3250 w Warner 285 from a 30 inch. I think 3150-3200fps is 600 rounds safe lol.

 

[Dave62677]

I’m 200 round count on my barrel, I guess is time to order 2nd and 3rd barrel

 

[BCX]

Yeah, i ordered 2 spares last month.

 

[ForgeValley]

Yeah, i ordered 2 spares last month.

Did you go with a Bartlein Mod bb again?

 

[BCX]

Yes, I have 4 on order. 7mm,30 cal and 2 338

 

[ForgeValley]

Yes, I have 4 on order. 7mm,30 cal and 2 338

Nice, what was lead time like? I probably need to get mine ordered for next year.

 

[BCX]

7mm and 338 prob EST 10 months, 30 cal 12 months plus

 

[babyguppy]

Question - (since most Bart's barrells are a year out). If this post should be somewhere else, let me know and I'll move it.
thinking KOM here with a 33XC and the 26# weight MAX. I was thinking of going with a BAT action. There are two to choose from.
BAT model M and model L. The Model L requires a 1.5 barrel vs 1.25 on the Model M. Also, if a person wants to move up to 37xc or CheyTec - you can use the Model L
BAT actions:

action-config-2021F.pdf (batmachine.com)​

BAT Model L –

load port opening 3.8 ;​

tenion 1.25”​

needs 1.5” barrel​

Bat Model M –

load port opening 3.35 ;​

tenion 1 1/8”,​

needs a 1.25 barrel​

1.25 barrels seem easier to come by a possible cheaper (and a little less weight)​

I was leaning towards the model L, in case a person wanted to jump up to 37XC or Larger.
Thoughts?
reason; I'll probably order the barrel before the action, due to wait time.
Thanks in advance