Author Topic: 7mmX (Read 936 times)

fwt1712 · « **on:** May 29, 2005, 10:12:39 PM »

I was just wondering if anyone had tried a 7mm or 6.5mm version of David Tubb's X cartridge i.e. 7-08 or 260 reamer run in short to use 22-250 brass. Just thought it might be a very neat, powerful enough round without the bother of going to custom dies e.g. IHMSA.

DanDeMan · « **Reply #1 on:** May 30, 2005, 07:38:35 AM »

fwt1712,

Way before Tubb started shooting the 6mmX a Californian gunsmith named Wally Muddemeyer (sp?). created the 7mm Wally (late 1980's). It was chambered using the 7-08 reamer held back 0.130". Dies were made by shortening 7-08 dies by the same amount. For brass one could use 300 Savage, 250 Savage or 22-250 cases. There are several top shooters in CA and AZ that still shoot this round. Case capacity is about half way between a 7BR and 7-08.

Tony Tello · « **Reply #2 on:** May 30, 2005, 07:39:47 AM »

fwt1712, several gunsmiths have done their own version of the 7-08 run in short to be able to use the 300 Savage brass or it's equivalent. The most common here in CA. is the 7-08 Wally.

The 7-08 chambering reamer is basically run in 1/4 inch short and the loading dies are trimmed by the same amount. I myself favor the 7MM IHMSA and have not used the 7-08 short but I imagine it would be very hard to tell the difference in their performance.

I have not heard of any silhouette shooters using the 260 short but I know a few that have gone the 6.5 IHMSA route.

In my opinion there has been no need to shorten the 260 because quite a few of us are using the 6.5 BR and the 6.5 improved versions like the 6.5 TKS and 6.5 VIKING instead, the very strong 6MM BR LAPUA brass has made it possible for us to achieve performances similar to the 260 using 5 to 7 gr less of powder.

If you are on a budget it may be better to do a 7-08 or 260 short because of the expense of buying custom dies and Lapua brass, either one would be a good choice but if you are recoil sensitive go with the 260.

DanDeMan · « **Reply #3 on:** May 30, 2005, 08:00:55 AM »

fwt1712,

I should have added that if you want to shoot a 7mm in silhouette, the 7BR is just about perfect. To shoot the long, heavy 7mm VLD's one should go with an 8-twist barrel. If one is going to shoot the 162 AMax, an excellent choice, than a 9-twist barrel is sufficient. For the short animals go with either the 162 AMax at 1,800 to 2,000 fps or the 139 Hornady SST at about the same MV as the 162 AMax ram load, 2,400 fps. VarGet with work most excellent with both loads.

For 6.5mm I'd go with the 6.5 BR if you don't want to go with custom dies. Just make sure the chamber is throated so that the 140-grain VLD ram loads have the bullet seated out enough to get 32 grains of VarGet in the case. You should use Lapua 6mm BR brass. It is not that expensive if you shop around and it will last 3 times as long as the cheaper Remington brass. I've got Lapua brass for my 6.5 TKS that has been fired more than 50 times and it is still doing its duty. Cheaper brass is false economy as I'd have gone through a lot of Reminton brass by now. An 8-twist barrel should be used. For CPT the 107 MK is fine at 2,600 to 2,700 fps. You should be able to push the 140-grain VLD's to 2,600 or maybe 2,650 fps.

Tony Tello · « **Reply #4 on:** May 30, 2005, 08:50:37 AM »

fwt1712, I posted my reply about one minute apart from Dan's without seeing his first. I don't want you to think that I am contradicting Dan since he is one of the most unselfish and knowledgeable silhouette shooter that I know. I take his advice seriously and many times I have asked him for it before doing a project.

Troy G · « **Reply #5 on:** May 30, 2005, 11:33:38 AM »

1712 you are thinking the exact same way I am. If Tubb's 3rd generation brass has all the bugs worked out of it I think it would be a great platform for a 7mm or 6.5XC.

I should be receiving a Hart 7mm blank sometime this week and will be trying a 7mm TKS and seeing how that works out for Standard. My goal is to equal the wind drift of a 6.5 TKS but exceed the energy delivered at the rams. If this does not give satisfying results I am going to go with a XC version either 6.5 or 7mm. The 6.5 has a better selection of high BC bullets with tough jackets so I would be leaning that way.

Let us know what you decide to do and what the results are.