My daughter's fiance called me today. He and a friend were looking at a rifle made on a Rem 700 action with a Lilja heavy barrel. The barrel was marked 270 Winchester/.304"NK. He gave me a call, wondering if I had ever heard of this one. From his description, it sounds like a long range target rifle. So..can somebody tell me about this caliber?
Thanks
Bfly

Well, it could be a target rifle, but most likely isn't. Though it has been used by a few for that purpose, the .270 just generally never seemed to catch on as a target shooter's favourite.

Most likely, it was somone's dream hunting rifle. Perhaps a long-distance precision rifle for something like coyotes. The barrel marking indicates a standard .270 Winchester chamber except with a tight neck.

Most cartridge brass at that size has neck wall thickness of .014"-.015". With a .277" diameter bullet, that thickness means a standard factory loaded cartridge or handload should run about .305" to .307" outside neck diameter when all loaded and ready to shoot. And I wouldn't sell a .270 rifle to a stranger to shoot factory loads in that had a neck any tighter than .311" to .314".

With a .304" neck diameter, the necks would need to be turned or reamed a hair before loading, in order to chamber safely and easily, but that would still leave them very nicely centered for good bullet alignment with the bore.

The danger is that with that particular size of neck a person might just occasionally be able to cram a factory round in there with a lot of bolt force, which could (and probably would) give dangerous pressures.

A hunter might want to turn the case neck walls to at the very most .012" thickness. That would give a loaded round diameter of .301"...or about .0015" clearance per side of the neck. Personally, for a hunting rifle I'd want more clearance than that...at least .002" clearance per side. To get that, necks would have to be turned to .0115" thickness.

If the barrel is in good shape, it might be an interesting rifle to own, at the right price.

A target rifle should be just about perfect with the .012" neck walls.

What Alberta Canuck is trying to say, translated into English, is that the rifle has a custom chamber with a smaller neck diameter than stock. It's a standard .270 winchester but if you shoot factory ammo through it you'll probably have pressure problems because of the tight neck. The ammo for it will have to be reloaded for it by someone who has neck turning equipment who can turn the neck of the case to the proper size.

Thanks,
Makes perfect sense to me. Hasd a 22 250 with a tight neck. Turns out that this fellow got this rifle as part of his Dad's estate. Dad was a serious gun guy, both a long range shooter and hunter. Sadly the estate sold off all the brass, bullets and dies before the sons were notified; family BS. We've all dealt with it. I'll pass the info on to him.
Bfly

I'm no gunsmith by any means, but wouldn't it be relatively cheap/easy to just run a standard 270 reamer into the chamber to ream out the neck to standard 270 Win dimensions?

that allows for brass that is .013" thick at the neck, and a .0005" clearance.

UPDATE.

I just mic'd my win factory brass necks and they mic out at .0134"-.0139"

sooooo, the chamber in question will require only turning off the high spots on the case necks and you will have a chamber/NK that will alllow brass to last for long periods of time. There will be very little expansion during firing, so work hardening will take longer.

quote:

Originally posted by Black Fly:
My daughter's fiance called me today. He and a friend were looking at a rifle made on a Rem 700 action with a Lilja heavy barrel. The barrel was marked 270 Winchester/.304"NK. He gave me a call, wondering if I had ever heard of this one. From his description, it sounds like a long range target rifle. So..can somebody tell me about this caliber?
Thanks
Bfly

My loaded 270 new cases neck dia is .303" if I mike dia of new case it's .301".

There no set standard on tight necks dia sounds like the 270 was made with just barely being a tight neck rifle. Alot of time they made what called match chamber reamer sound like that rifle was set up that way.

One thing you want to make sure of if he decides to buy that rifle is get dies/cases and loading information and make use unloaded fired rd fit in that chamber.

I find it interesting that neck walls of brass these days is so thin. The figures I used are from my Winchester .270 brass of about 30 years ago (early 1980s). It measures just under .015" neck wall thickness right out of the box. (I still have about 8 boxes of that batch, new and unused.)

quote:

Originally posted by Alberta Canuck:
I find it interesting that neck walls of brass these days is so thin. The figures I used are from my Winchester .270 brass of about 30 years ago (early 1980s). It measures just under .015" neck wall thickness right out of the box. (I still have about 8 boxes of that batch, new and unused.)

I hate to say this but the 270 brass I measured came form the era when Win sold unprimed brass package in 20rd boxes. I don't shoot the 270 much and I have appr 5 new boxes each of unprimed Rem/Win brass.

I have loaded 270 Win ammo that mics from 304 to 307, so.....be very careful--JMO, KNOW what the particular ammo will be shot in that rifle, or do as another poster suggested and have a smith ream the neck to SAMMI specs