Anyone else have trouble getting a X-Calibur 6.5CM Shorty Barrel to shoot?

[NHPiper]

Have a new gun built on a Trued R700 action with an X-Calibur Remage 16" barrel. I have done all my shooting suppressed. I love the idea of a short 6.5CM. In NH, I rarely get the chance to shoot beyond 500 yards and occasionally will get out to 900, so the shorter barrel isn't restrictive since I am not pursuing ELR. One thing I have noticed is that I get a fairly bad mirage through my Steiner much faster than longer barrels, even with the suppressor wrapped. It seems to shoot factory Hornady 140 ELDM well under 1/2 MOA (ave. 2388fps), see the last pic in bottom right. All shooting is done prone from a bipod with a bag in the rear.

Starting off, I did 10 round ladder tests with 123gr SMKs, 130 ELDMs, and 130 RDFs and swore I found a generous accuracy node between 42.8-43.9gr of H4350 with the 130 ELDMs, but further group testing at 100 yards was awful (well over 1MOA).

I moved to 140 ELDMs and shot quick 5-round groups with H4350 charges at 41.8, 42.3, 43.3, then did the same for 140 Custom Comps. The ELDMs with 41.8 had very little vertical stringing, but some horizontal and the 140 ELDMs with 43.3 had the opposite. I am going to reshoot both of those charges with the ELDMs, shooting one 5 round group at each charge suppressed and then taking the suppressor off in case that has something to do with the flyers I am getting (This hasn't happened on any of my other guns, it is a Sig Titanium SRD 7.62 QD can).

Anyone else struggle to find a load for a short X-Calibur Barrel?

 

[Nimothy]

How often do you clean? did you follow a break in procedure? New barrel and 50 round could give you some bs. Also I think barrels settle in between 50-100 rounds and that’s when you should start developing loads not off the bat.

 

[NHPiper]

Yes i did the break in. I started load testing around 50 rounds in. Must not have waited long enough. Printed these groups this weekend using 43.3gr H4350 (2600 fps) and 40.0gr of Shooter's World S065 (2408 FPS), both with 140 ELDM. Will be heading to 200 and 300 yards to test both charges, plus an increased charge of S065 to see if I can gain some velocity.

 

[Nimothy]

I think I’d be very happy with 2-3 of those groups especially if they were repeatable. About velocity I read on the internet especially when people refer to dasher/br based cartridges that there loads read like “30 grains of varget..... 3100fps or in creed 41.5 2875.....” and here I am a cunt hair away from blowing the fuckin primer out and still 100fps less than them. So either subtract 75-100 FPS or just come to terms that you draw the short straw on having a fast barrel with EVERY rifle

 

[NHPiper]

Ya i would take the accuracy over velocity. I didn't get any pressure signs with H4350 until I got closer to 43.9gr, and even at that point it was a minor ejector mark on every 1 in 5 pieces of brass with no primer cratering, so I think there is room if I decide to go with 43.3gr or knock it back to 43.1-43.2gr.

After having a .260 Rem I liked to run hot, and having to knock out several heads of brass after case-head seperation, I have no desire to repeat that exercise.

 

[Danattherock]

No personal experience but I was at a PRS match yesterday talking with a fellow competitor who was having the same issue with the same barrel manufacturer. All barrels are different so take that for what it's worth. But literally yesterday I had a guy that's a good shooter complaining his xcalibur wouldn't shoot. if you do change barrels at some point I would highly suggest you look at Hawk Hill barrels in Virginia. They are among the very best money can buy.

 

[BoilerUP]

43.3gr H4350 seems warm for a 140-class bullet, but if no obvious pressure signs then send it.

2600fps from a 140 through a 16” barrel is pretty damn good IMO, and you’ll likely pick up a bit of speed hitting 150-200 rounds.

What did the common 42.3-42.5gr charge give you for velocity?

 

[NHPiper]

Didnt chrony loads in that range. I didnt chrony a 41.8gr charge at it was 2480 fps.

I am getting velocity readings from a magneto speed without my can on, so I bet im gaining an additional 20-40fps since im shooting this exclusively suppressed.

 

[supercorndogs]

What all has been done to your action? If threads have been trued up, the threads on the barrel need to be oversized as well.

 

[kindabitey]

I'll second what @supercorndogs said. The X-Caliber Remage pre-fits are for unmolested Rem 700 actions. Not only have the
threads been opened up on a trued action, the front of the action has at least been skimmed a few thou. to square things up.