Hey everyone, was curious if anyone has had the same problems I've had with superior shooting systems 6xc loaded ammo. It is the coated 115 dtac bullet with nose ring. Just finished my custom 6xc Kelblys atlas tactical with a kreiger 1-7.5 twist barrel finished at 22". I ordered 100 rounds of this ammo just to get some rounds through it and have fire formed brass. First round was VERY over pressure. It had gas leakage around the primer and part of it was deformed. I reluctantly chambered and fired another round, and although no primer leakage, still over pressure, with heavy bolt lift. Ive fired several more and some are heavy bolt lift, some are fine. Avg velocity was 2920 fps with a sd of 20, and groups are no better than 1.5 inches at 100 yards, maybe my rifle just hates this ammo, but for how he markets this stuff id expect it to at least be somewhat consistent and safe.
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Superior shooting systems loaded ammo problems
- Thread starter Tjn260
- Start date
One challenge with 6XC (in my experience) is that there are multiple reamer specs out there that lead to issues. I suspect first question from SSS will be who cut the chamber and which reamer was used.
The "original spec" reamer was for the 22-250 brass derived 6XC. The reamer print was updated later for the CIP Norma brass. Suspect new SSS 6xc Ammo is in Peterson brass. There is now a 6XC2 reamer that Tubbs does not claim.
I had an early 6XC with the "original spec" reamer that was problematic with Norma 6XC that SSS was selling. SSS told me to have the "newer" reamer run through the chamber and that solved my issues. When that 6XC barrel was consumed - I moved on to 6BRA and 6Dasher.
Take a fired case (as it came out of the chamber) and see if a 6mm projectile will fit into the fired case. On my 6XC with "old" chamber, a 6mm bullet would not fit into the fired case. The "old" chamber was not allowing the brass to expand enough thereby causing the hard bolt lift, higher pressure, etc.
Okay, so I think I've found my problem. I called and confirmed my reamer specs, and it looks like i have .130 freebore. The necks are expanding about .004 so there is no problem there. I believe the bullets are just too close to the lands which is causing too much pressure. I appreciate the feedback and will try some 108 bergers and see how they play out.
From David Tubbs himself (daddy of 6XC) - this is from the SSS website:
"Helpful tips from David Tubb regarding the 6XC The 6XC -- what works for me. I shoot the 6XC, not the 6XC II. For 6XC reamer I use a .470” base diameter .278” chamber neck diameter .160” freebore (straight section) and 1 ½ degree lead. The reason I use a .278 neck is it allows the bullet to be centered without the case neck influencing alignment and the carbon buildup in the neck won’t start showing higher pressures (+50 rounds). I also don’t want to neck turn anything. The neck runout on either the Norma or Peterson 6XC is typically .0015” I like Dave Manson and Hugh Henriksen for 6XC reamers. Please make sure you double check with them on the reamer dimensions - stated at the top of this write up. 2.780” is approximately the OAL measurement for a new chamber with a bullet just touching the rifling (slight differences from rifling configuration can occur). I like to try shooting 115 DTACs with either a .010” to jump or .010” engagement into the rifling. Remember your pressure will quickly increase when seat your bullet into the rifling. My tried and true load is 39.5 grains of H4350 using the coated DTAC 115s achieving velocity of 2950 fps in a 26” barrel. The useable range of the 6XC is 38-42 grains of H4350 so go up by a half grain each time you try a load and see what works for you. Another good powder is 42-44gr H4381sc. Using a 26” barrel or longer, velocities of 2950-3100fps can be achieved."
I would reach out to David Tubbs - he was very helpful with my 6XC questions.
"Helpful tips from David Tubb regarding the 6XC The 6XC -- what works for me. I shoot the 6XC, not the 6XC II. For 6XC reamer I use a .470” base diameter .278” chamber neck diameter .160” freebore (straight section) and 1 ½ degree lead. The reason I use a .278 neck is it allows the bullet to be centered without the case neck influencing alignment and the carbon buildup in the neck won’t start showing higher pressures (+50 rounds). I also don’t want to neck turn anything. The neck runout on either the Norma or Peterson 6XC is typically .0015” I like Dave Manson and Hugh Henriksen for 6XC reamers. Please make sure you double check with them on the reamer dimensions - stated at the top of this write up. 2.780” is approximately the OAL measurement for a new chamber with a bullet just touching the rifling (slight differences from rifling configuration can occur). I like to try shooting 115 DTACs with either a .010” to jump or .010” engagement into the rifling. Remember your pressure will quickly increase when seat your bullet into the rifling. My tried and true load is 39.5 grains of H4350 using the coated DTAC 115s achieving velocity of 2950 fps in a 26” barrel. The useable range of the 6XC is 38-42 grains of H4350 so go up by a half grain each time you try a load and see what works for you. Another good powder is 42-44gr H4381sc. Using a 26” barrel or longer, velocities of 2950-3100fps can be achieved."
I would reach out to David Tubbs - he was very helpful with my 6XC questions.
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