I have a line on a sportered Winchester p14 which is still in its original 303 British chambering. It could serve as a "truck" gun, but I am wondering what potential it has as the base for a build. I am led to understand that the p14 is pretty much a p17, but in 303 Brit instead of 30-06. Does it have the same possibilities for a build as a p17 ? Seems to me I've seen discussions about the p17 serving as a base for cartridges such as the 375 H&H, 416 Rigby. What's possible for the p14, and what makes sense for it? Does it merit the required investment for any sort of build at all?

I believe the P14 is a better platform for a big bore because there is some additional metal surrounding the bolt face.

Bolt is the same size as a Mauser's. Receiver ring is actually a bit smaller. The only reason a P14 might considered suitable for a big cartridge build is that the action is big and heavy so one might want to justify the weight.
I've actually heard some claim the P14is a good choice for a magnum because you don't have to open up the bolt face. True enough but you do have to spend hours opening up the magrecess and building a new mag box. Or you could start with a 17 and spend fifteen minutes opening up the bolt face.
I think the P14 is a great choice for a 303 British or 30/40 Krag. Life's too short to waste time on any radical alteration to end up with something which might not work all that well anyway.
I was recently sent a P14 which was a failed attempt at a conversion to 416 Rigby. It took me six hours of work to get it to where it would feed acceptably and two more to pare off some of the ugly. You can buy an action suitable for a big cartridge and build on that for less than a P14 build would cost and the result would probably be quite a bit better too. GD

We used to sporterize old military rifles when they were cheap and plentiful.

There were fewer new rifle choices then also.

My late dad bought a P-14 that had been sporterized by using the military stock. It was drilled and tapped and as you know they were 30-06's.

I shot a buck in VT with it when it had the peep rear sight and he got me a Lyman 4X All American the next year and he fitted a Bishop stock to it. He did the metal over in Black Oxide which was the rage in the 50's.

Although the rifle was accurate it was heavy and clumsy. The stock was not checkered nor did it have a pad. I got a couple of deer with it and some chucks. While it had a decent safety that held the firing pin overall the rifle was too big for me.

It's gone and I am glad of it. I have better rifles now.

So if you have nothing to do this winter but have a bench and a vise along with tools you might make a hobby out of it. I would not.

To add now that I looked for a picture on the net to post here I had forgot about those ears that they had!

Thus I would dump the rifle as is if it is at all military looking still. That's what's the rage today, the military look even the old stuff. Just dump it and buy a nice new rifle!

P14s were chambered in 303 British, not 30-06 Springfield.

There's no such thing as a P17. The proper designation is US M1917, sorry just a peeve of mine.

I' personally wouldn't dump a bunch of money on a P14 custom. If the work was nicely done, buy it right and use it as is.

Thanks for your comments guys. I did some other investigating as well, and finally decided to back away from the deal ... didn't matter anyway, as the rifle sold in the meantime. As mentioned, it had already been "sportered", and really didn't look all that bad. If it shot as well as the seller indicated, it would have made a good truck gun. It's not that I needed another, but it seemed like such a bargain, I just didn't want to passit up.

Lugs on the M17 bolt are tapered and when opened leave very little metal surrounding the bolt-face. The P14 has a radiused lug allowing more metal to remain ... but we're talking 505Gibbs sized cartridges.

These days, save your money and buy a CZ550.
Cheers...
Con