The official Mike Bellm's

Bellm TCs

TC Contender, G2, Encore/ProHunter Performance Center


Redding dies tends to be the most compatible with the original factory 7mm-08 barrels rechambered to .280 Improved. Full length 2-die set $95, checked against the chambers I cut and shortened IF necessary.
Starting from the original diameter of factory 7mm-08 chambers, I of course can make them larger, but not smaller. Thus the fired case diameter of .280 Improved at the "expansion ring" will be at least as large as the original 7mm-08 chamber, and in some instances must be enlarged a bit more in order for Redding dies to size the expansion ring any at all. But the result is a very nice match up of fired v. resized case diameters.

Nosler reloading data for .280 Rem. Ackley Improved

The Encore mechanism is NOT as strong as most all bolt actions made for comparable cartridges. Therefore, bolt action guns will stand up to higher pressures without problems than will the Encore.

My advice for the Encore is to stay with loads with the slower powders that push 140 gr. bullets approximately 3,150 fps, which in the real world is normally all that factory level 7mm Rem. Mag. loads produce. This is the approximate pressure level you should be operating at in the Encore. In other words, resist the temptation to squeeze out all the velocity Nosler established for bolt guns.

140 gr. is the optimum bullet weight for most hunting situations unless the game requires more penetration or if shooting longer ranges where a higher ballistic coefficient is called for.

With any load worked up, harder unlocking of the barrel is your signal to back off the powder charge! Don't overwork the Encore frame.... or "Pro Hunter" frame. They are one in the same.

If you opt to push the Encore to its limits and stretch the frame or bend the lower lip of the barrel lug, you are the one responsible for any damage done, not me. Be a maximum velocity freak at your own risk.

Best respect this most excellent long range cartridge for what it offers in the Encore without stretching the limits. If you REALLY do NEED more horsepower, step up to factory level .300 Win. Mag. And if you do shoot .300 Win. Mag. DO have me extend the extremely short throat for better accuracy! Factory throats are both too short and cut too large in diameter for best accuracy. Extending the throat at minimum diameter boosts accuracy a bunch! ...... both with factory ammo and handloads with bullets seated out.

7mm-08 rechambered to .280 Ackley Improved at work in New Zealand.
Jake F., New Zealand, March 2012. AWESOME trophy! Congratulation, Jake!
Thanks for letting us be a part of your success. Mike Bellm

From Mike F. :

I know you guys are busy, but I through you might like to see some pic's of my son's recent trip to New Zealand with a Bellm TC in 280 AI. Everything was taken with one shot each.
My son said that his guide was kinda rolling his eyes over the single shot, but he changed his mine when he saw this Red Stag drop in his tracks with one shot at 170 yds from the 280 AI

Thanks for helping me put togather a real shooter!!


.... and his ram.

TC "Pro Hunter" factory 7mm-08 rechambered to .280 Imp.

100 yard accuracy.
As with all data, user assumes all liability for use of published data. Always start with charges 10% lower than listed, then work up in small increments watching for any indications of excess pressure.
Courtesy C. Guntert

Two holes, 3 shots!

The load specifics are:
TC Encore Frame and TC ProHunter Barrel Converted by Mike Bellm from 7mm-08 to 280 Ackley Improved
1x hinge pin
Barnes 140 Grain TSX Boat Tail Bullet
57.5 Grains of IMR 4831 Powder
Federal GM210M primers (Gold Match)
Seated to lands
.001" headspace
Results: 3 shots at 100 yards = 0.268"

200 yard .918" group at approx. 3180 fps.

Load was 58 gr. IMR 4831 with 140 gr. Barnes TSX BT bullets.

The End Product We Work For,
Courtesy C. Guntert

in this case a nice Mojave Desert buck.

Refer to this page for availability

Impressive accuracy with Nosler 140 gr. FACTORY ammo at 200 yards.
Bergara standard contour 24 in. 280 AI custom chamber cut by Mike Bellm. Nosler factory 140 accubonds 200 yards. Kinda makes me not want to reload!!!!! Getting boring. Gonna have to get another barrel from ya'll....

Excellent TC Dimension Rifle Accuracy, 7mm-08 factory barrel rechambered to .280 Ackley Improved, Bellm muzzle brake machined into the barrel.

I am set up to rechamber TC Dimension rifle barrels as well fixtured to index muzzle brake ports without having the rifle receiver here.

Eric Ebbinghaus of Haus of Arms shows us how the TC Dimension .280 Imp. shoots!

...and the results in the field:

See Haus of Arms, Click Here!
Marty Ebbinghaus and his son, Eric, above, share our passion for the TC guns and are a good source for TC products. Good folks, too!

Special note from Redding regarding size die adjustment:
Richard Beebe at Redding informs me their .280 Ackley Improved size dies are made .008" shorter than SAAMI minimum and should permit bumping case shoulders back. This may or may not be enough shorter.

Frequently shooters are not able to push shoulders back simply because the shell holder is not hitting solidly on the bottom of the size die.

In other words, if your resized cases stick out of the chamber too far, be sure the shellholder presses solidly against the bottom of the die before you decide the shoulders cannot be pushed back as required. Flexing of the press can leave a gap between the shell holder and the bottom of the size die. So make sure there is no gap IF it appears the size die is leaving the cases sticking out of the chamber to far.

Mike Bellm: If cases still stick out too far, then it may be necessary to remove material from the bottom of the die so as to permit bring the shoulder inside the die closer to the shell holder/headstamp of the case.

Redding and/or CH-4D .280 Ackley Improved dies are kept on hand, $95.
Dies are checked against the chamber I cut for the best matchup available and shortened as needed so you can bump case shoulders for correct headspace.

.280 Ackley Improved Videos, click here!
We have put up video demonstrating how to get correct headspace for the improved cartridges with .280 Ackley Improved the subject of this video.

It is VERY important to understand several key points about headspace and size die adjustment, clearly demonstrated in this video and Part II.

Be sure to see them. You may need to watch them several times to get the concepts, but once you do you should have great success not only with the .280 Ackley Improved, but working with all bottle neck cartridges as well.

Order your 7mm barrel forchambering to .280 Imp. from MGM. Click here.
Order your 7mm barrel made however you want from Match Grade Machine. You have the option for them to cut the .280 Rem. Improved chamber or have them forward the barrel to me to custom chamber. Total cost with shipping and handling for me to do the chamber work is $150.

Your final cost is $150 plus whatever MGM charges for the barrel.

For those like me that like to see a minimum amount of case bulge at the head of the fired case, starting from an unchambered barrel lets me cut a smaller proportioned chamber, BUT it then also requires choosing resize dies that size cases smaller than Redding dies typically size to. With the size die you intend to use in hand, I can give a good match up of chamber and size die.

IF you have a .280 Improved die set and want to know what it sizes to at the expansion ring, run a fired 7mm-08, .270 Win., .243 Win, or similar fired case from a factory chamber through your size die to see what it sizes to, and go from there.

Send your 7mm-08 for rechambering to .280 Imp. per this page. Click here.
Prices, procedures, and policies for having us rework your barrel.


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