The Accurate Reloading Forums
7mmSTW to 300 H&H
13 October 2009, 22:09
BigBullet7mmSTW to 300 H&H
Gentlemen,
This is a question carried over from the medium bore form. Is it possible to convert a 7mmSTW to 300 H&H without a lot of hassle? This is on a Winchester Mod 70 Classic with claw extracter.
Thank you for your help.
13 October 2009, 22:34
ramrod340Rebarrel, new or shorten ejector,bolt stop and remove magazine rear spacer. My 7stw started life as a 7 mag. I have built them both ways. altering the factgory parts and simply buying new parts made for the long magnums. Half dozen of one six of the other. I never alterned the ejection port and it ejects empties and live rounds with no problems.
As usual just my $.02
Paul K
14 October 2009, 02:31
StonecreekI think that Ramrod must have misread your post as the 7mm STW and .300 H&H have the same length of case and same overall loaded length. Nothing regarding ejectors or magazine spacers is required. I assume that you ask the question only because you suspect that the feed rails may be wider for the STW, which has a less tapered case.
I'll lay a hunert dollar bill on the table that says the feed rails are identical for the two cartridges and nothing other than rebarreling is required. However, the simple way to find out is to just put a handful of .300 H&H cartridges in the magazine and see if they feed properly. They'll go far enough into the chamber to allow you to determine this.
14 October 2009, 04:38
JBrownquote:
However, the simple way to find out is to just put a handful of .300 H&H cartridges in the magazine and see if they feed properly. They'll go far enough into the chamber to allow you to determine this.
+ 1
And "if" it doesn't feed the 300 H&H dummies because the rails are too wide up front, I "think" it would be hard to make it feed correctly.
Jason
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14 October 2009, 08:11
ramrod340quote:
I think that Ramrod must have misread your post as the 7mm STW and .300 H&H have the same length of case and same overall loaded length. Nothing regarding ejectors or magazine spacers is required. I assume that you ask the question only because you suspect that the feed rails may be wider for the STW, which has a less tapered case.

Yep sorry about that. I had 7mag on the brain. Mine will feed a 375 until the bullet stops it. Can't say on the 300 since I don't have a case.
As usual just my $.02
Paul K
15 October 2009, 17:10
BigBulletOK, checked the feeding of the 300 H&H cartridges in this action and they feed very well. So I believe I have a good action for this conversion.
My question now is it better to rebore or rebarrel. It looks like reboring can be less expensive without the reblueing, but is it an option on this 7mmSTW barrel?
Thank you for your help.
15 October 2009, 17:50
ramrod340quote:
My question now is it better to rebore or rebarrel. It looks like reboring can be less expensive without the reblueing, but is it an option on this 7mmSTW barrel?
I've normally seen the new barrel with blue being as cheaper or cheaper than a rebore and rechamber. Also I've seen different quotes for a "rebore" and "rebore & chamber"
might look at
http://www.itdcustomgun.com/While I haven't had my coffee yet today a 300H&H won't clean up a 7STW chamber. Don't even think a 300H&H AI would without major setback. I have no clue if you can go from .284 to .308. Only time I would even consider a rebore would be for a unique factory contour
As usual just my $.02
Paul K
16 October 2009, 06:54
Stonecreekquote:
While I haven't had my coffee yet today a 300H&H won't clean up a 7STW chamber. Don't even think a 300H&H AI would without major setback.
Correct. A .300 H & H won't even clean up a 7mm Rem Mag chamber. If BigBullet wants to go from 7mm STW to .300 H&H his only choice would be to rebarrel.