Author Topic: Rechambering a .270 (Read 2820 times)

kmitch199 · « **on:** February 27, 2003, 03:39:16 PM »

I have an older Ruger 77 in .270 that I'm thinking of rechambering. I would like to keep the .277 bore and not spend too much money. I was thinking .270 improved but what might be some of the other options.
Thanks in advance for any info you can give me.

Advocate · « **Reply #1 on:** February 27, 2003, 05:24:05 PM »

Check out the .270 Gibbs.

Nobade · « **Reply #2 on:** February 28, 2003, 02:29:18 AM »

The Gibbs and the Weatherby are the obvious choices. Not a whole lot out there for .277 bore.

270Handiman · « **Reply #3 on:** December 07, 2004, 06:59:19 AM »

Can you re-chamber a standard 270 to 270 WHY in a standard remchester action? Just wondering if the pressures would be too high.

Thanks

Graybeard · « **Reply #4 on:** December 07, 2004, 08:13:39 AM »

Quote

Can you re-chamber a standard 270 to 270 WHY in a standard remchester action? Just wondering if the pressures would be too high.

Yup sure can. Bolt work will cost ya some extra bucks but can be done. Might need to do a bit of change up to make the belted round feed too but it shouldn't be a real problem for a person deserving the title of gunsmith. Pressures are not that different and the rifles are chambered to other rounds with same pressure so no problem there.

jackfish · « **Reply #5 on:** December 08, 2004, 04:42:57 AM »

The 270 Weatherby in a 22" barrel would be little better than the 270 Win. Same condition almost killed the 264 Win Mag when Winchester produced a 22" version. Pretty hard to improve on the 270 Win in a 22" barrel. Really save yourself some money and leave it alone.

Catfish · « **Reply #6 on:** December 08, 2004, 03:20:49 PM »

If you want some advice, forget it. If you have it rechambered to .270 Weatherby you increase your velosity from about 3,100 fps to 3,300 fps. Increaseing your max. point blank range on deer from from about 370 yrds. to abt. 390 yrds. This will not only cost you for the barrel work, but also for the bolt face work. When reloading , if you were useing imr- 4831 powder you would go from 57.1 grns. to 70.2 grns. of powder. Looks like alot of money for little gain to me.

260 AAR · « **Reply #7 on:** December 08, 2004, 07:41:34 PM »

How about a 270/284? I made up several of these a while back and the owners say they`re getting almost WBY velocity, great accuracy and less recoil. Just a thought!

Aloha, Mark

riddleofsteel · « **Reply #8 on:** December 12, 2004, 01:43:34 AM »

Henry Ball of Bill's Custom Guns in Greensboro, NC uses a 270 wildcat based on a 300 Win Mag case. It fits in a standard action rifle but the bolt head does need to be modified. This has been his pet deer rifle for many years now and he never gets tired of talking about its virtues. However the advice given here is sound. The .270 is a beltless magnum already and there is not much that you can do to it that you would notice in field experience on real game animals.
The 270-.284 is an interesting project I had not thought of. Of course is performance would be almost identical to the 6.5-.284 and as such it would be a good performer. If you go that route you may see some extra accuracy from the short, fat case however accuracy may be governed by you barrel quality, crown ect.

hkg3k · « **Reply #9 on:** December 12, 2004, 02:41:36 AM »

Has anyone tried Accurate's MagPro powder? It's a slow ball powder designed for the new short mags, but looks as though it was taylor made for the .270.

Accurate max loads get 3200+fps with a 130gr Ballistic Tip and 3000fps with 150gr with Sirrea boat tail.

http://www.accuratepowder.com/data/PerCaliber2Guide/Rifle/Standarddata(Rifle)/277Cal(7.03mm)/270%20Winchester%20page%20235%20and%20236.pdf

This is getting very close to the .270 Weahterby mag factory loads, and with this powder, the .270AI would most likely easily surpass the Weatherby mag.

Graybeard · « **Reply #10 on:** December 12, 2004, 07:46:17 AM »

Quote

How about a 270/284? I made up several of these a while back and the owners say they`re getting almost WBY velocity, great accuracy and less recoil. Just a thought!

Since the .284 Win. is shorter than the .270 Win you can't just rechamber to it. And besides you get zero case capacity increase. So if someone is pushing .270 Whby. velocity they are using proof pressure level loads to get there. There are no free lunches. To get more velocity you MUST do one of two things. You either increase case capacity and burn more powder or you increase pressure. The .270 already operates at pretty much max safe pressure for modern bolt guns.

Quote

Has anyone tried Accurate's MagPro powder? It's a slow ball powder designed for the new short mags, but looks as though it was taylor made for the .270.

Yes I have. Where data is available it is truly great. Excellent accuracy and a serious velocity increase. But sadly data for it is extremely limited. In the applications it seems to me it should really shine no pressure tested data is available.

260 AAR · « **Reply #11 on:** December 12, 2004, 09:55:54 AM »

To make a 270/284 from a standard 270 win you move the shoulder forward .275-.280 and chase the threads and the cut to proper length and rechamber. The ones I have done " seem" outdo the standard 270 by a bit. Accuracy and velocity. Is it worthwhile? If you want something different I guess it is. Still end up making 1-3 a year.

Aloha, Mark

Graybeard · « **Reply #12 on:** December 12, 2004, 01:04:48 PM »

Mark, what do you do about the fact the barrel has to be shortened to do this and then no longer fits the contours of the inletting? Since the barrel is larger at the rear than at muzzle and is shortened from rear it seems to me the inletting is no longer gonna be right and there is gonna be space to be filled with something? Correct or not?