6xc velocity issues

[Chuckw]

i finished a 6xc a couple of days ago and intend to shoot only the 115 d-tac for now. it is a surgeon rsr and 1-7 pac-nor super match at 26". i started with h4350 as is suggested but ran into pressure at 37gr and slightly less than 2800fps. at 2700 fps it is shooting less than 1/4moa but that speed doesnt interst me in the least. i am looking for mid 2900's. i tried a case full of h1000 next and that was good for 2750 and zero pressure with outstanding accuracy. lastly i tried 42 gr of ramshot hunter. it averaged 3025 with no pressure but accuracy was over 1/2moa which doesnt interest me either! my question is, will h4831 get me the velocity i am wanting without the pressure issues or is there another temperature stable powder i should try to get me there? it appears that h4350 is just too fast burning in this barrel. thanks in advance.

chuck

 

[Mudcat]

what brass are you using?

 

[Chuckw]

remington 22-250. i know winchester is harder brass but that doesnt explain why the ramshot was able to make over 3000k easily with no pressure. do you think the slower h4831 will get me there?

chuck

 

[40X Guy]

Try the SC version of the H4831, it may be what you are looking for with the 115's

Frank

 

[Chuckw]

i will try that. i shot some more h4350 and i am not sure if it was a product of the new bore or what but i was able to get to 39.5gr and 2975fps before the bolt got sticky. i backed it off to 38.8gr for a velocity of 2925avg and it shoots great. i am hoping that the h4831 will get me really close to 3000fps before i see pressure.

chuck

 

[fivering]

Try Re-19.

 

[Bob3700]

Chuck,

The issues you are facing with 115 DTAC bullets in an XC is exactly why I switched to the 243 SLR. I was running the DTAC at 2980 out of a 30 inch tube and primer pockets didn't last very long. That was with Winchester brass which is pretty light compared to other makes. I was using H4831sc to get there but the high pressures just took their toll. Plus, I really didn't like shooting those loads in 90+ degree weather in competition.

I think the XC is a great cartridge for 107 gr bullets but the 115s are just a bit too much to expect 3000 fps with any sort of brass life.

Just my experience.

Bob

 

[wboggs]

I used to shoot DT 115's at 2950 using H4350 and got .25-.35 moa accuracy. Have switched to the Berger 105 hybrid and it seems to be better in all respects. You might want to give it a try with your H4350. Mine doesn't require anything exotic for .25moa.
Bill

 

[shooter65]

Maybe a bad lot of 4350? I have heard of that before. 105 Hybrids are where it is at with the 6xc. I am using 38.5 gr of 4350. 22 min of elevation out of an 26" 8 twist Bartlein to 1k.

 

[GermanS1]

Chuck, the DTAC 115 has a longer bearing surface than the Berger 115 and that will limit you in terms of powder charge and velocity. I would suggest trying the Berger and H4831sc. Having said that, I know that big MV numbers are exciting, but being able to actually see a 100 fps difference when shooting is pretty iffy...

 

[Lostcreek]

Chuck
I am shooting the 115 DTAC with 40 grs. H4350 with Norma brass and wolf primer out of a 7.3 twist 5c Broughton 30 inch barrel at 3050 fps,with no pressure. It looks like the brass will last a long time. I don't know if it is norma brass or the 5c design that allows the velocity with no pressure signs. I am leaning toward the Broughton barrel giving me the velocity. The accuracy is very good.

 

[Chuckw]

i appreciate all the responses. i am going to give the h4831 a try. i knew when i chambered the barrel up that the 7 twist might inhibit velocity some. i will be content with a mid 2900's load with stellar accuracy and good brass life. hopefully the h4831will do that. if not, i guess i am going to be happy with 2925.

chuck

 

[GermanS1]

Be sure to get the short cut version H4831sc, with the 6XC case size, it'll make a useful difference in the powder charge that fits before compressing.

The 1:7" twist won't inhibit accuracy. Pressure differentials and thus velocity with faster twists is negligible.