6 creedmoor velocity/pressure

[DLT]

Short backstory, rifle is an all factory savage model 10 with 600ish rounds on her. I have been shooting my decent load of 39.5gr of H4350 in Adg brass and standard large rifle primer at 3015-3030 fps with a 105 hornady bthp in the 26” barrel. The load shoots good one day and not so hot on the next and I decided I would run another powder test. On either side of 39.5 I had the same point of impact but the groups opened up. I went on up in .3 increments all the way to 40.7 The charges at 40.1, 40.4, and 40.7 well pretty tight and impacted at the same point on target or very close. I thought I noticed 1 snug bolt lift at the 40.7 charge and the group opened up a fuzz. I have flattened primers which I had at 39.5 but I don’t see a swipe or an ejector stamp on the brass. Is 40.4 out of the ballpark as far as safety goes ? I see load data between bullet manufacturers is all over the place. Thanks just curious as to what others is shooting

I’d like to add that my current brass is shot up after at least 9 firings on it. Wonder if that could explain the hard bolt lift I felt on that one case ? . The primer pockets are still tight but the web is getting the ring around it down towards the case head so I know it’s weak and getting tossed before I have a separation

 

[ShtrRdy]

It seems if you keep the velocity around 3050 fps for that weight bullet you should be okay. Have you tried different seating depths?

 

[Idaho-Lefty]

Might try some,.. Sierra 107 grain, SMK's,. set bullet IN to, a Lite Jam ( Back off, a Bit on, Max Charge, tho ! ).
My 10.5 Pound, 6 XC puts them ( 5 shots ) into, One Hole from, the LOW 2's to, the 3's.
3,015 FPS with, 40.7 grains of, StaBall 65, in Norma Brass, F-210M prs ( 6 xc Data ).
Agree with ShtrRdy, keep the velocity down to 3,050 to 3,020 FPS for, best accuracy and "Play" with,..
Jump's and Jam seating. Clean Barrel with, BoreTech Eliminator ( Throat Carbon ) and Barnes C-10 ( Copper Removal ). Might also get, some New Brass ( Peterson, Norma, Lapua or, ADG ).
Do you HAVE "Good" Dies with, Low TIR Bullet "RunOut", like,.. Forster ?

 

[DLT]

It seems if you keep the velocity around 3050 fps for that weight bullet you should be okay. Have you tried different seating depths?

Yes I did do a test. I had a big wide node on it

 

[DLT]

Might try some,.. Sierra 107 grain, SMK's,. set bullet IN to, a Lite Jam ( Back off, a Bit on, Max Charge, tho ! ).
My 10.5 Pound, 6 XC puts them ( 5 shots ) into, One Hole from, the LOW 2's to, the 3's.
3,015 FPS with, 40.7 grains of, StaBall 65, in Norma Brass, F-210M prs ( 6 xc Data ).
Agree with ShtrRdy, keep the velocity down to 3,050 to 3,020 FPS for, best accuracy and "Play" with,..
Jump's and Jam seating. Clean Barrel with, BoreTech Eliminator ( Throat Carbon ) and Barnes C-10 ( Copper Removal ). Might also get, some New Brass ( Peterson, Norma, Lapua or, ADG ).
Do you HAVE "Good" Dies with, Low TIR Bullet "RunOut", like,.. Forster ?

I did run the 107smk for a little while, I like that bullet but my rifle likes the 105 better for what ever reason. I use reddings full length die with guts removed and a mandrel. I seat with a hornady seater with their micrometer top. I hate reddings standard seating die. Thank goodness I have 1 box of 50 adg brass I never put to use.

 

[MTlager]

With large rifle primer brass I had best luck with br2 primer. I like slower powders and heavy bullets. 115 Berger’s , 108 EH and 112 match burners all work good fir me, but I mostly use small rifle primers . I just tried some superformamce the other day and got some real good accuracy and velocity. Normally use RL 16 and 26.

 

[DLT]

With large rifle primer brass I had best luck with br2 primer. I like slower powders and heavy bullets. 115 Berger’s , 108 EH and 112 match burners all work good fir me, but I mostly use small rifle primers . I just tried some superformamce the other day and got some real good accuracy and velocity. Normally use RL 16 and 26.

I might shop around for h4831 or vhitavori powder line. Alliant is hard to find and bad expensive when you find it. Hodgdon load data maxes out at 42.4 which I went 2 grains under at 40.4 but I have to be running faster than their claim of 3070 as I was 3030 with just 39.5