6mm-TCU

Not exactly the 6mm TCU, the 6X45. This is the .223 Remington necked up with the the factory shoulder and neck length. The firearm is a custom XP-100 with the action trued, laminated stock, and a lightweight barrel to stay in the Long Range Handgun Weight limit. The barrel is a 1 in 9" twist taken off a custom Model 70. I've shot it with both a Burris 10X Long Eye-Relief scope (hunting) and a Weaver 36X target scope (target). 

Bullets are both cast and jacketed:

Jacketed (for prairie dogs)

• Berger 68 grain Match
• Sierra 70 grain match
• Sierra 95 grain Full Patch
• Sierra 100 grain SPBT

Cast:

• RCBS 243-095-SP
• RCBS 243-100-FN
• SAECO 85 grain TPR (actual cast weight 93 grains from this mold)
• SAECO 105 grain TPR (experimental)
• Eagan 68 grain TPR
• All loads were shot of used monotype alloy to gain greater velocity 

Results:

• Jacketed bullets in the range of 90 to 100 grain bullets shot sub-minute when the nut behind the grip did his part. 
• These were shot at high pressure and velocity for varmint
• Cast bullets that shot well,are the RCBS 243-095-SP and the SAECO 85 grain TPR bullets up to 2300 fps
• The cast were shot at lower velocities and run through QuickLoad to estimate velocity
• Sub-minute groups up to 2100 fps.

The XP-100 is a swap-barrel currently with a .17-.221 Fireball barrel on it. After prairie dog season, I will switch it back and start experimenting with the 6X45 again.