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Posted: 1/19/2008 5:30:51 PM EDT
| SSK lists this as a caliber they chamber on their site. Has anyone tried this? It seems attractive because there is no special mags or bolts needed and brass is easily found. |
Yes, I have. Special mag mods are needed because of the front indented mag rib, which binds-up the fatter 7mm bullets after more than 6-7 rounds are loaded. But a Dremel and hand files provide magazines at will... 17-round modded mags (with 30rd followers):  I'm hoping Magpul's 20rd Pmags are usable with just a little internal filing on their tiny internal guide edge for a full 20rd mag. |
He called the "Master Blaster" didn't he? It was intended for use in the Long Range stages of "The Masters" handgun competition. If I remember correctly, he later worked up a semi-auto version that was sort of a forefather to the LR300. |
That is correct, it was originally built for the Masters tournament. I even have the iron sight tube for it. I used it briefly for silhouette. I'm not aware of the semi version. He got away from civilian gun smithing when he started with his LR guns. He also built me a beautiful compensated 1911. |
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Go for it chris. My dad used to shoot that round in a 200 meter silhouette match from a TC and now has a bolt rifle chambered in 7TCU. Other than it is in a 223 case, I don't know that much about it. What ballistic benefits does it offer over say a 6.8SPC? Do you have any detail pics on the mag mod? Who made your barrel and did the gas system have to modded? Wes |
I load to the max OAL that will fit in the magazine. The heaviest bullet I have used is 140 gr
The necks are wider and would bind if that rib wasn't removed. |
Only ballistic benefit the 7mm TCU has over the 6.8 is the ability to load 120gr bullets, which are missing in the line-up of available bullets for the 6.8 SPC. The 6.8 shoots bullets 15% faster and flatter than the 7TCU. The 7mm TCU loaded at magazine length is much like a 7.62x39, at about 93% of its power, but shoots flatter at distance, and uses 556 brass, mags and bolts. I had the upper built in 2005, as I got tired of waiting for 6.8 brass to come along. I'd prefer not to advertise the builder, as I was ripped-off for the cost of a bolt+carrier, which was to be included in the upper's price. If you ever have someone make an upper for you, get their quote with all specs in writing. The barrel is a 16" HBAR 1-9 twist with carbine gas. Gas port was originally around .063" and after an unsatisfactory trip back to the builder and then back to me, I used a cordless battery powered drill to open it by .005". If you make one, go with 1-10 twist, carbine gas, and make it an 18" for a little better performance. Magazine modification pics:      |
Loading to 2.260". 110 and 120gr comressed loads. 2,300 and 2,275fps respectively from my 16". Hot. Powders so far: IMR 4227, IMR 4198. The 4227 is higher pressure and works the action reliably, but is harder on brass. The 4198 gives higher maximum velocities with lower pressures and is "nicer" to brass. |
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