Home Forums Hunting & Shooting Winchester Collectors Information request about M-70 barrel

When looking through the safe yesterday for a barrel, I ran across another barrel unexpectedly, which I didn’t recall having. Photos below.

Obviously it’s a Win M-70 Pre-64 300 H&H bbl for a standard rifle, rechambered at some point to 300 Wby. Confirmed current chamber by placing a fired 300 Wby case in the chamber.

IIRC rechambering like this became somewhat popular in the 1950s & 1960s so I assume this may have happened then.

I am not an expert on Pre-64 variants so have a couple of questions for the experts:
1) based on the roll mark, what would be the approximate time period this barrel was manufactured - pre-war, transition, other?
2) Who is/was R. W. Lathrop? I assume he’s responsible for the rechambering?
3) Is the barrel tenon thread diameter & tpi the same on the Pre-64 and the Classic CRF LA?

Although I’m not a Wby fan, I’m considering using this barrel, which seems to have pretty good rifling and chamber to external visual inspection, either on an old non-collectible Pre-64 receiver or on a Classic. I haven’t run a borescope down the bore yet but may do so if the idea seems feasible.

Any opinions on this thought?

Answers to your first question....
- Winchester cataloged the 300 H&H Mag until 1963
- Winchester began using the one piece die in 1950 and added the H&H at that time
- Does the barrel have an integral or soldered front sight ramp? soldered would be 1952 or later
- If there is no two digit under barrel date stamp your barrel was manufactured after 1956
A Google search revealed that R.W. Lathrop was a Seattle, WA gunsmith
No idea about the barrel threads, someone with more knowledge will be around to answer that question.

I like how he engraved it with his name and the chambering. As for the year it was manufactured, after '56 if there is no barrel date stamp on the underside. Since you did not say it has one, I'd assume it doesn't. That would have also answered your question. So it is not prewar. It has to be from a '57-'63 model. The 300 H&H stamping like your barrel has, was used after 1950 (1950-1963). Wondering why the barrel was removed from the action?

I’ll check for the under barrel stamp as I haven’t examined it for that. I don’t know the reason it was removed as I don’t remember how or when I acquired it. Probably a project I didn’t get the time to do.

I suspect the TPI is the same but will check it along with the FS. I’ll also measure the diameters so I can get a better idea of potential fit.

Thanks all for your responses.

After a closer look at the barrel’s identifying features I found that:
1) the FS is soldered
2) on the underside of the chamber there are stamped a linear witness mark, 300M, and the 2 digits 55.

Based on the information provided by the M-70 experts here, it seems this barrel was manufactured in 1955 as a standard model 300 H&H and then rechambered to 300 Wby sometime thereafter.

Visual inspection of bore and chamber still show sharp rifling and no signs of erosion. Think I’ll need to proceed with at least a trial swap out to install this barrel and see if it shoots.

Probably will use a 416 Rem Mag donor - I’ve never warmed up to this cartridge - sitting there and not being used. Other option would be finding a used but usable p-64 action, though one already opened for the H&H class is less easy to find these days.

Sounds like you got it. Those H&H receivers are out there, you just have to look for them. I know where one was one a while back, that I could have bought for $800.00, because it was already rechamberd to 300WBY. It was actually a nice rifle that I almost bought, but I already have one myself and couldn't see spending the money. I don't think a lot of guys actually get out and look for deals like I do, so maybe your chances of finding one will be slim??? Maybe someone here has an H&H receiver or barreled action they would let go of? Beware though, the actions by themselves (with bolt and btm metal), usually sell for over $1,000.00 when you do find them. Good luck with your search. That barrel deserves to be used, if it is as nice as you say it is. Mine is definitely a shooter!!

Huh. Saw a nice condition 300 h&h sell for $1000 last week. Only negative was a pad. Guess someone got a deal.

Yep. Not a great deal, but I digress. We know what I pay for them.

Barreled action rechambered to a 300 weatherby for $800 bucks is a good deal. Complete rifle in a 300 H&H for a 1k not a good deal??

The rifle I saw was complete for $800.00. It was a pretty nice rifle, but also had a recoil pad installed. Didn't look like it was shot much, and had an old leupold on top. Back in 2019, I paid $499.00 for basically the same rifle. However, I'm one that prefers the 300wby over the old H&H though.

Gotcha, 2019 sure was a different time. I remember picking up a stainless classic for $450 bucks.

It's slightly different. The market is kind of soft right now though. So in comparison, it's very similar. Just bought this classic compact 243 for $599:


Along with other pretty good deals I've gotten on pre 64's and classics. The op may be able to find a good deal on an H&H rifle, and use his barrel on it.

That was 2018. I also did that, right after you did. 7WSM in fact. Gunbroker of all places too. Mine was $500 though, so not quite the deal you got.