I have a 300 H&H that shoots about 1/2 MOA vertical and 2 1/2 to 3 MOA horizontal with the loads I've tried so far. I've resisted glass bedding it again so far.
I'm curious, There's a screw that is through the fore arm that must have been to tighten the barrel to the forearm. Do you guys tighten this, keep it loose or remove it for best accuracy? Any tricks?

Man, that is a million dollar question. I have had to tighten it to farmer tight on a few and some I just removed it. I would experiment with it some. I'd try tightening right down first and take it completely out for the next group. My P64 338 liked it tight while I have seen others that do fine without it.

Is the rifle and stock all original?

Pretty much whatever works for you. On my P64 .300 H&H I have the frontmost screw just tight enough that it doesn't fall out. If you have a torque wrench take it with to the range and and tighten it at 5 inch/lbs increments and see what happens.

It’s original.

PLUS 1 TO Pugs Post, just above. Likely the best answer IF the rifle is yet with ostensibly original descriptor. Glassed, technically altered. You need to decide. The screw with bit of the mildest 'lock-tight' genre screw securer, as required.
Just my take
Best!'
John

If your rifle has the Redfield JR one-piece mount with dual opposing windage screws I would check the tightness of those rear scope mount windage screws first. If you have a bore sighter you can see movement if the windage screw is loose.

Scotty's post was the best answer. However, I'd add that if the op wants to glass bed a stock, buy a used one that's already been altered, like with an addition of a recoil pad. I wouldn't glass bed the original 300H&H stock. There are guys here that believe the pre 64 model 70 doesn't need glass bedding, but there are multiple reasons to glass be a barreled action into a stock. The op states one of the most important reasons to glass bed a rifle. Also, my take on pre 64's with the forend screw found on the standard weight models. The ones I have had, have shot most accurately with the screw removed and the barrel freefloated. That is of course after a proper glass bedding. That is the only way they are going to shoot accurately and retain the same poi year after year. With the forend tension screw, you are always going to have to check to make sure your poi hasn't changed, due to changes in humidity and different barrel to stock contact. Also, if the op's rifle is shooting that poorly, I'd remove it from the stock and check for cracks. If this is the case, all bets are off and I'd fix the crack and glass bed the sob...

Excellent thing to consider. If it has windage adjustable rings, now would be a good time to throw them away and buy something more suitable and nicer.. There are many newer options out there now that work much better and offer more strength and reliability than that type of mount..

The mounts are Leupold, quick disconnect type and they are tight. I have also a 375 H&H (AI unfortunately) pre-64 and it has identical mounts. I have a spare scope with mounts that will inter-change with either.
I'll fiddle with the fore-end screw. I bought a POS pre-64 stock here on the fire, I'm not sure if it will fit. I'll give it a try.

Glass bed and play around with the POS stock and keep the original as is. Another option is Mcmillan, Brown Precision or any other after market stock you can live with. It really depends on what you want to use the rifle for.

Initially that those two rifles were going to Africa with me - That was the plan. Now, I’m thinking the 300 deserves to get hunted by me at least once. A Wyoming cow elk would be fine.

When a hunter gets old, each hunt, even a cow elk hunt becomes precious. But there’s a problem too. What rifle? What load? This might be the last hunt…

I too am interested in pet loads for the 300 H&H. I have a pre 64 that I am reviving with a remodeled rollover stock (what I have available currently). Intent is to use it for mule deer, black bear and moose.

I've had a pre-'64 .M70 .300 H&H for a good while. Very accurate with several bullets, but the zero wanders slightly from time to time. Not enough to really hurt anything as I don't shoot at extreme ranges. I can live with that as the rifle is all original and I don't want to bed it. I've had little experience with the forearm screw; this probably varies from one rifle to another.

Yeh, my 375 doesn’t have that screw, the stock I bought didn’t have a place for the screw.
I wonder if the attachment to the barrel comes off easily? I’ll have to look.

A lot of aftermarket stocks make no provision for the barrel tension screw. You don't have to remove anything, except for the screw itself. Id do like Scotty said and try it with the screw snug, then try it with very little tension. Let the rifle tell you what it likes

OP, here is a great thread to read:

Pre 64 model 70 accuracy

This will be a good read for a lot of you guys. A lot of good guys in it sharing their wisdom and experience. Another one of those threads that makes me miss ol Bobin..

Give the screw some tries and see what happens.

Doesn’t sound like you wanna put another stock on it. Most all of my P64’s have gotten McMillans but I’ve kept the Featherweights in wood, well, a couple of them.

That 300 H&H should work just perfect for cow elk. I’m always on the lookout for a 300 that I can swap into a McMillan.

I have a pre-64 300 H&H, it wears a receiver peep and fires 220gr partitions over h-4831 sc, it, like my pre-64 264 both fire more accurately with the screw just started a couple turns, i have blue loctite on the threads to keep from losing it, that said, the little 22 Hornet is snugged down medium tight, i think it's barrel with such a small bore makes it less of an issue.

I'll dig my old 300 H&H out and send ya a couple pics Big B, i love that damn thing, and yes, cow or bull elf would be cake inside 300 yards with the peep.

I'm just the opposite. I'm always looking for just the right Mcmillan I can put my 300 in.. ha ha. I'm eyeballing one right now, but its a slightly heavy pre 64 pattern.

Well, if you do ever get bored of it, let me know, my buddy in Lyle can hold it till we see each other next time. Makes the transfer easy...

My 300 will never be altered while I own it. I’m assuming I could have only afforded the 375 because someone had to “improve” it.

I have a few really light rifles based on the 700 or 721 actions. I just put light stocks on factory rifles usually but I have a couple with light barrels too.

The 300 and the 375 were made in 1953-1955 time frame if I recall correctly.

Its your rifle and yours to do with how you wish. Sounds like its ill shooting right now, I hope you get it figured out and can use it on your hunt..

I'd probably not install a diopter sight on a 300 Mag of any flavor. But for those who wish it, the following: The Lyman 48 seems generally the most popular of the breed. From 1917, three models. First 150 scale, second 125 scale and last... depending on sub model, but generally 50. 'Range diminished reflecting the fact of 'reaching out', typically with scopes! I have a few Model 70s with Lymans (including the Model 58, a $$ lesser model.
Ironically, 'arriving' installed on my pre '64 .338 Mag! Moving to a particular point concerning these fine Lyman 48 sights. The 3rd edition - limited range, but a "no inletting feature" on many rifles. Meaning no horrible stock carving to install. My .338, such style and 'achieving' no-inletting which is also subject to stock not being too thick in the sight installation area. I've also heard of folks shimming this Third Model to avoid slight inletting which, is essentially the same as 'slight pregnancy', in collector terms!
Some pix of my Win 70 'pre', .338 Win Mag, Super Grade w/such sight below.

Best!
John

John, I have to ask. What does the Lyman sight have to do with this thread. However it is very cool. Start a thread on your sight and how your 338wm shoots, then I can counter with how well my m96 shoots with its aperture sight. Then when I get my front aperture from Sweden, I can then counter again with some sub moa groups.. This with irons at 100 yards. Indulge me please.. For what it is worth, I don't think this is the answer to the OP's problem. I'm trying to stay out of the convo of this thread, as he has some major mechanical difficulties going on. Simple to address for some, maybe not so simple for others...

Hey BSA, A damn good question re my diopter sight remarks in this Thread! Yesterday, pinging on gunner 500 Post concerning "peep sight". Copying it & rushed response half day later in MS Word. Not checking intermediate posts having returned to the main topic... My 'Bad!'
Thanks for voicing what others here likely thinking!
Just going to leave it as "general info re Lyman 48!
Best!
John

LOL, and i threw mine in because i shoot a peep sight on my 300 H&H, meaning, if i can belly flop my big ass across and bench with no rear bag and shoot 3-4 inch groups at 200 yards im GTG, also meaning, ii may not matter exactly how much, if any pressure my forearm screw is or is not applying to this particular rifle, i'd need to scope it to see the difference.

It all remains good, let us continue to shoot rifles, kill animals, enjoy good smoke, drink, and our women!

I have had great accuracy luck in 2 rifle with 165 gr sierra game kings that are the hollow point version. I shoot mine with 66 grains of IMR-4350, Norma brass, Fed 215 match primers. Of course work up what is safe in your rifle.

I finally got the 300 H&H out for testing after glass bedding and DBC coating. (Winchester brass)

300 H&H Winchester, Pre-64 70, 168 Nosler E-tip, 215 Primers, 67 grains IMR4350 0.81 MOA first group tested

1.3 MOA second group - but I called the high one - otherwise 1 MOA

I have a land-owner Buck permit - season opens tomorrow. I think I'll load up a box of 168 E-tips and carry the 300 H&H. I have it sighted in at 2.5" high at 100 meters. Should be dead on at 275 yards.


Funny thing is, I have not been able to get these bullets to group in my other 300's or one of my '06's. I'll be checking this rifle out more when weather permits and different seasons don't interfere