cataway,

I have cut a lot of chambers for the 7mmX307 in the Encore as well as having cut a rim counterbore for their 7mm-08 barrels, which allows the use of the 307 win. case. Just run a 307 Win. case into a 7mm-08 size die and you have a rimmed 7mm-08...

There are a lot of accuracy issues with T/C barrels and that's one reason I have made a living off of "fixing" them for almost 25 years now. When T/C cuts a chamber in one of their barrels, they use a modified "drill press" for this instead of a lathe. Their chambers for the most part are very seldom in alignment with the bore and this is the biggest reason a lot of their bharrels won't shoot! That is, unless they are rechambered to a longer cartridge that will allow for the proper alignment between the chamber/throat/bore...

I see more 223, 7mm-08 and 308 barrels from T/C than most all others calibers combined. These three cartridges seem to be the most popular but most of the time, the accuracy potential falls way short from what the customer is expecting from them. This is where I come in. When I receive a "problem" barrel from a customer, this is what I do with each of the calibers listed:

223 - This one has a tendency to have a throat length that is both, on the long side and oversize. In this case, I rechamber it to what I call the 22 SHORT PREDATOR. This round is based on the full length 5.6X50R case. It is designed with minimum body taper and a 40 degree shoulder angle. This round is enough longer that it allows me to be able to cut a completely new throat section and correct for any misalignment that exists between the chamber/throat/bore. The 22 SHORT PREDATOR is loaded with a set of 223 Ackley Improved dies and a LEE Carbide 357 magnum die. The 223 A-I die sizes the neck and bumps the shoulder while the LEE die sizes the base where the 223 die stops short. With the new 28" Pro Hunter barrels that T/C now has out, the ballistics of this cartridge very nearly duplicate that of the factory 22-250! This is a very effecient cartridge design and one that can be had in the T/C Contender, Encore and H&R single shots...

7mm-08: This chambering from T/C also lacks a lot to be desired! Poor chamber alignment is this cartridges biggest problem when it won't shoot accurately in the Encore. To cure the problems associated with this round, I designed what is called the 7mm PREDATOR! This round is based on the full length 444 Marlin case necked down to 7mm. It has minimum body taper and a 40 degree shoulder angle. This cartridge is enough longer than the 7mm-08 that it allows the chamber to be completely recut and properly aligned with the bore. This round is loaded using a set of 280 Ackley Improved dies that I modify to fit the chamber that I cut...

308: Same problems as the one above, poor chamber to bore alignment! I chamber this one to the 308 PREDATOR, which is also based on the full length 444 Marlin case necked down to 30 caliber. This one is loaded using a set of modified 30-06 Ackley Improved dies. This round is by far my most popular because it can be had by rechambering the 30-30 in the T/C Contender and the 308 in the Encore as well as the H&R...

When I set a barrel up for rechambering, I dial in off the bore. Then I will take a boring bar and cut the chamber square to the bore to correct for any misalignment. If the chamber is not bored first, before the new chamber is cut, the reamer used to cut the new chamber will just follow the old chamber and you will still have a misaligned chamber! By boring away the old chamber, you are assured of cutting a chamber that is in perfect alignment with the bore. There is a lot more to this than just cramming a reamer into an old chamber and hoping for the best...

A properly chambered barrel, or I guess I should say "rechambered" barrel, along with an 11 degree target crown at the muzzle, willoffer any of these single shot barrels their greatest accuracy potential. I shoot a 308 PREDATOR in an H&R Ultra and it will consistantly shoot 1/2" groups at 100 yards while it would shoot ne better than 1 1/4" when it was a factory 308 Winchester...

In any of these break open single shots, when possible try to get a barrel that will allow for a rechambering option just in case it does'nt shoot well enough for you like it comes from the factory....... Just a thought....

DAVID