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Come on David - we can take it

Look on this as me thinking out loud.

I do not want a factory chambering, if I have to order a reamer I may as well choose something a bit different and the thinking behind this has always been to build a reasonably compact and lightweight rifle based on an owned donor action that would allow us to both shoot at 25-50 yards plus get out to maybe 100 yards on occasion. Given that keeping the muzzle energy down for the short stuff is a consideration I could have just gone for a .38Spl or similar however the donor has a .308 bolt face and I have no desire to take the other logical route of the .45ACP.

We always have several hundred fired .308 cases around us and 9mm/.355" bullets are very cheap and easy to source in both cast and jacketed so why not put the two together and in principle this does work however there are some considerations. Firstly the 9mm-08 is very close to the .358 Winchester and if someone was rash enough to stuff a .358 Win round into the chamber and close the bolt it could well end in tears, secondly the OAL of the 9mm-08 is going to end up at around 2.500"/63,5mm at best versus the OAL of the .308 at 2.800" ish so .300" shorter which given the shape of the bullets may lead to feed problems when cycled quickly. On a plus side with a rifle weight of around 4kgs max there is never going to be a lot of recoil when pushing a 147-158 grain bullet down range at 1200fps for the short stuff plus it can soon be wound up to 2500fps or quicker and still stay way inside pressure limits.

There is an alternative, use the 30-06 Springfield as a parent case. The 30-06 is 63,3mm and opening it out to 9,0mm is going to give a developed case length of very slightly less. Add a bullet of around 16,0mm and you end up with an OAL of very close to 2.800"/71,1mm so all but identical to a CIP .308 Win which means it will feed from the magazine. One possible downside is a 9mm-06 is going to be rather close to the 9,3x62 and even closer to the .35 Whelan which uses .358" bullets (Think of it as a long .358 Win)

There is another consideration and that is the 30-06 is not as popular as the .308 over here which means brass will never be as plentiful.

I could always modify the magazine with a .300 packer at the back to allow the 9mm-08 to sit slightly forward and possibly modify the feed ramp of the donor to slick things up however I always wanted this to be something that could be built without having to modify the actions and magazines so they could always go back to their original use.

Argh.......

ovenpaa wrote:Look on this as me thinking out loud.

I do not want a factory chambering, if I have to order a reamer I may as well choose something a bit different and the thinking behind this has always been to build a reasonably compact and lightweight rifle based on an owned donor action that would allow us to both shoot at 25-50 yards plus get out to maybe 100 yards on occasion. Given that keeping the muzzle energy down for the short stuff is a consideration I could have just gone for a .38Spl or similar however the donor has a .308 bolt face and I have no desire to take the other logical route of the .45ACP.

We always have several hundred fired .308 cases around us and 9mm/.355" bullets are very cheap and easy to source in both cast and jacketed so why not put the two together and in principle this does work however there are some considerations. Firstly the 9mm-08 is very close to the .358 Winchester and if someone was rash enough to stuff a .358 Win round into the chamber and close the bolt it could well end in tears, secondly the OAL of the 9mm-08 is going to end up at around 2.500"/63,5mm at best versus the OAL of the .308 at 2.800" ish so .300" shorter which given the shape of the bullets may lead to feed problems when cycled quickly. On a plus side with a rifle weight of around 4kgs max there is never going to be a lot of recoil when pushing a 147-158 grain bullet down range at 1200fps for the short stuff plus it can soon be wound up to 2500fps or quicker and still stay way inside pressure limits.

There is an alternative, use the 30-06 Springfield as a parent case. The 30-06 is 63,3mm and opening it out to 9,0mm is going to give a developed case length of very slightly less. Add a bullet of around 16,0mm and you end up with an OAL of very close to 2.800"/71,1mm so all but identical to a CIP .308 Win which means it will feed from the magazine. One possible downside is a 9mm-06 is going to be rather close to the 9,3x62 and even closer to the .35 Whelan which uses .358" bullets (Think of it as a long .358 Win)

There is another consideration and that is the 30-06 is not as popular as the .308 over here which means brass will never be as plentiful.

I could always modify the magazine with a .300 packer at the back to allow the 9mm-08 to sit slightly forward and possibly modify the feed ramp of the donor to slick things up however I always wanted this to be something that could be built without having to modify the actions and magazines so they could always go back to their original use.

Argh.......

:lol:

That was pretty much my thought process about the Ishy!

What is the donor rifle, BTW?

I will post a picture of the donor rifle up in the next few days.

Q. How do you keep an idiot in suspense?

A. He's demonstrating it to us....

meles meles wrote:Q. How do you keep an idiot in suspense?

A. He's demonstrating it to us....

The answer is out there. You just have to look for it! :55:

I would prefer to hold back with further details of the actual rifle itself at this stage however I do have the action and magazine nearly 'in the white' next to me right now, it needs a bit of work to get it as I would like it to be and there are a couple of tweaks to add as well however this is an evenings and weekends project as I have more than enough to keep me going during the week days. Really this is a relaxation project, something to take my mind off everyday stuff.

Of course this does not stop further discussions regarding the ultimate chambering for the rifle.