Velocity issue with my new build 6XC

[40X Guy]

My new 6XC mid season mid size build with 28 inch Bartlein tube based on Rem 700, Shehane tracker was my to do today as far as breaking in the barrel. Chamber is .268, I turned necks on new 6XC brass to achieve a .266 loaded round with 38.5 grains of H4350 under a 107 Sierra Mk and lit off by Fed 210GMM primer @.010 off lands. After reading for a few months here and a few other places I was expecting 3000 FPS and was looking for something between my future 6BR and my current 6AI's, but speed as shown was highly disappointing. But accuracy was not bad considering i was cleaning and shooting for 5 hours and 25 rounds. Where do I go next for powder? I really don't like RL (17) series of powders but i am thinking H4831SC or N160? Barrel is broken in and is very smooth cleaning with no copper build at all. But i would really like to push these 107's over 3000. i don't believe that H4350 is gonna get it done in my combo for speed. Heres a reading on the 10 shots from today with my Oehler 35P, and my chrony is fine.

Frank

 

[bozo699]

Frank,
My 1:7.5 30" Krieger shot 3030 with 115 VLD's and 39.5 grains of H-4350, I don't know why you aren't getting at least 3000 fps, are you using coated bullets like moly? I think your velocity will even be lower with the H 4831sc at least mine lost velocity with it and RL-17 was faster but lost accuracy.
Wayne.

 

[WyleWD]

You may just have a slow barrel, but before I gave in to it, I'd try some N-550 and /or N-560. WD

 

[Mudcat]

What brass are you using?

With a 28 inch bbl, you should be able to get over 3000 pretty easily with H4350. Which, btw, is the powder of choice for the 6xc. I have tried all of the other listed and could never really get more speed and accurancy than I get with H4350...which is probably the perfect powder for this cartridge.

John

 

[bozo699]

What brass are you using?

With a 28 inch bbl, you should be able to get over 3000 pretty easily with H4350. Which, btw, is the powder of choice for the 6xc. I have tried all of the other listed and could never really get more speed and accurancy than I get with H4350...which is probably the perfect powder for this cartridge.

John

I agree with everything John has said.
Wayne.

 

[40X Guy]

What brass are you using?

With a 28 inch bbl, you should be able to get over 3000 pretty easily with H4350. Which, btw, is the powder of choice for the 6xc. I have tried all of the other listed and could never really get more speed and accurancy than I get with H4350...which is probably the perfect powder for this cartridge.

John

Thanks for the replies everyone, I'm using the Norma 6XC brass and bullets are naked 107 MK's, I went with H4350 after reading numerous posts here about it being the go-to powder in 6XC. But may not be in mine. I was thinking some Vihtavouri powder is gonna be my next test today, these velocities not much more than a 6BR . I will post back later today with results of both N550 and Hodgdon Hybrid V 100.

Frank

 

[Mudcat]

Norma brass. There is your problem. For whatever reason, Norma brass in the 6xc, regardless of generation, just doesnt work. Switch to Winchester or Lapua and I bet you immediately see a difference in what you can do with your loads. I have a bunch of Norma 6xc brass and it gets used for low pressure practice loads only.

John

 

[40X Guy]

Norma brass. There is your problem. For whatever reason, Norma brass in the 6xc, regardless of generation, just doesnt work. Switch to Winchester or Lapua and I bet you immediately see a difference in what you can do with your loads. I have a bunch of Norma 6xc brass and it gets used for low pressure practice loads only.

John

John, thats interesting about the Norma brass, wonder why? But I'll give it a go today as I already have some N550 loaded up and ready. I do have a box of 22-250 Lapua brass ready if needed.

Frank

 

[bozo699]

Frank,
I won't argue with John because sounds like he has tested this theory but I have only used Norma and Tubbs and I have 200 rounds of Norma on its 5th reloading with no issues and no problem to 3000 fps with just one more grain of powder than your using, which should give you another 100fps but you would still be almost 100 fps short, and I was using 8 grain heavier bullets. I wonder if 3 inches longer barrel could make that much difference?
I am interested how the 550 is going to work for you, best of luck Frank.
Wayne.

 

[2644ever]

Norma brass is stout for a good reason: less capacity, at least the one I used to work with in .22-250..
On another hand Norma's .300 Win Mag has the highest capacity ever. Go figure.

 

[bozo699]

Norma brass is stout for a good reason: less capacity, at least the one I used to work with in .22-250..
On another hand Norma's .300 Win Mag has the highest capacity ever. Go figure.

I found that out the hard way, 70 grains of rl-22 behind a 210 VLD in a Norma case is fine but don't try it in a RWS case at least if you ever want to see your primer again :
Wayne.

 

[mikecr]

40x, why did you think 38.5 of H4350 would produce 3000fps?

Your fill ratio is really low, your off the lands, your pressure is very low.
With this, you're a full 2gr below 3Kfps, and you could go another 4gr before reaching SAAMI max @ 3150fps.

Nothin wrong with Norma brass folks..

 

[40X Guy]

40x, why did you think 38.5 of H4350 would produce 3000fps?

Your fill ratio is really low, your off the lands, your pressure is very low.
With this, you're a full 2gr below 3Kfps, and you could go another 4gr before reaching SAAMI max @ 3150fps.

Nothin wrong with Norma brass folks..

I agree there is nothing wrong with Norma brass after todays testing, but for some reason H4350 is way off the mark and I was hoping for mid 2900's with 38.5, but any way i tested N550 with an OCW test and came up with a powder node from 39.5 to 40.5 grains of N550. The best group was at exactly 40 grains and netted me an average speed as seen on my Oehler of 3,079fps. i was testing in .5 grain increments so I could see what was happening a little faster, at 40.5 grains of N550 the speed jumped way up to 3,155 average(still no pressure signs in my rifle) but group opened up. I was shooting all my rounds at .010 off the lands. Darn near as fast as my 6AI shooting 107 MK's at 3180(mild). i want to retest in .2 increments starting at 39.5 and go up. i did shoot 3 rounds loaded with Hodgdon Hybrid 100V but i will not disclose the amount as it was sticky bolt lift, group was terrible and it was only 3,020 fps average. I just got this rifle done a week ago and was thinking I could get lucky the first go a round like I did with my 6.5X47 and i was wanting to take the 6XC to a match next saturday. But i may have to try the H4350 again and get the load density up. I am running H4350 in my 6.5X47 at 41.2 grains and the load is slightly compressed so maybe thats what I have to do with this rifle? Thanks everyone for all the help!!!

Frank

 

[WyleWD]

I'm Not really surprised with your findings on the N550 using the Norma brass. Just out of curiosity..... what was the extreme spread of the 40gr load???

Also, I totally agree that 4350 is the go to powder for the 6xc, however there are circumstances and conditions where R-17 or N550 will beat the pants off of it for speed or accuracy and in a fair number of instances.... both. (Or at least that is what both my rifles show). WD

 

[mikecr]

I don't mean any disrespect & wanna help.
N550 is a poor case fill, and a very HOT powder(which will hurt barrel life).

I think you should step up to a real load in either H4350 or IMR4350.

 

[40X Guy]

I don't mean any disrespect & wanna help.
N550 is a poor case fill, and a very HOT powder(which will hurt barrel life).

I think you should step up to a real load in either H4350 or IMR4350.

Mike, I appreciate the help and also from everyone else here of course, and no disrespect taken at all. I agree that the N550 is a very poor case fill, and after shooting 6 rounds that barrel was warmer than usual, thats the last thing i want to do is end life of barrel prematurely. I'll start over with the H4350 and go up in .2 increments until I find the accuracy/speed node it likes then do a seating depth test. If I end up around 3,050-3100 life will be good, my spread with the N550 40 grain load was 22, not good, but looked good on paper.

Frank

 

[RAGGED]

How many rounds thru the tube? I know my last few 6mm bbl's sped up dramatically after 100rds, hitting peak around 150 or so, easy 100 FPS on some loads.

 

[spclark]

Norma brass. There is your problem. For whatever reason, Norma brass in the 6xc, regardless of generation, just doesnt work.

Hmmm.... I know you shoot a lot more than I do John, but my experience with Norma 6XC brass hasn't been the same.

I'm running 8208XBR since late last year behind (hBN home-coated) Berger 105VLD's @ 3,100 fps using Norma brass & Wolf LR primers with excellent results even out to 1,200 yards.

Quadlite + 30" Bartlein 5R 1:7.8, ~ 450 rounds thru it since late 2008; @ 600 it's an X every time if I'm doing what I should be, regrettably not with consistency.

 

[40X Guy]

How many rounds thru the tube? I know my last few 6mm bbl's sped up dramatically after 100rds, hitting peak around 150 or so, easy 100 FPS on some loads.

I only have 39 rounds thru the barrel, and that thought crossed my mind also. Am definately going back to H4350 and see what happens.

Frank

 

[40X Guy]

Update on my 6XC and H4350. Took it out tonite and performed an OCW test after also removing the ejector spring in the Rem 700 action. This was shot at 100 yards with little to no wind and at the high charge of 40.5 there was zero pressure, but velocity is still not there? I may very well keep going up. But the 39.0 charge looks very good with 3 in same hole. I shot the test round robin and 10 minutes between each 6 rounds. Sierra 107's at .010 off the lands and fed. 210 GMM primers. .268 neck chamber and .266 loaded round with the Norma brass.

Frank