Why has my 300H&H gone from ok to fantastic groups?

[Vintageguy]

Ok, here’s a brain teaser for your consideration. I bought a pre 64 Winchester model 70 in 300 H&H a few years back with the intent of taking it to Africa. I bought factory Hornady 180 grain ammo and shot it but my best groups were 1 1/4 inches. So I began working hand loads with various bullet weights,…the usual. But still groups of about an inch were it but nothing to be too excited about. Usually when I go to the range I typically take at least two guns and most days I could get really nice groups from the others but this one just ok. So I’m confident it wasn’t me.
Then a few months ago what you see attached started becoming fairly commonplace and it is shooting groups like this with factory loads and not just my hand loads. My only theory is despite the gun being made in 1955 the bore was never broken in. There was no copper visible in the rifling and it will spin a bore brush off my cleaning rod despite it’s having a free spinning handle. The only 30 cal rifle I have that will do this. Anyway, it’s bore’s rifling shines like a penny now. I haven’t had a rifle change like this without my knowing I caused it and how but I’d be interested in hearing your theories.

 

[Racinjason]

Ok, here’s a brain teaser for your consideration. I bought a pre 64 Winchester model 70 in 300 H&H a few years back with the intent of taking it to Africa. I bought factory Hornady 180 grain ammo and shot it but my best groups were 1 1/4 inches. So I began working hand loads with various bullet weights,…the usual. But still groups of about an inch were it but nothing to be too excited about. Usually when I go to the range I typically take at least two guns and most days I could get really nice groups from the others but this one just ok. So I’m confident it wasn’t me.
Then a few months ago what you see attached started becoming fairly commonplace and it is shooting groups like this with factory loads and not just my hand loads. My only theory is despite the gun being made in 1955 the bore was never broken in. There was no copper visible in the rifling and it will spin a bore brush off my cleaning rod despite it’s having a free spinning handle. The only 30 cal rifle I have that will do this. Anyway, it’s bore’s rifling shines like a penny now. I haven’t had a rifle change like this without my knowing I caused it and how but I’d be interested in hearing your theories.

I would say you are on the right track...Could have very well purchased a diamond in the rough that somebody never shot (or shot extremely little). Otherwise I would say it just needed a good deep cleaning to remove fouling, but from what you described, id lean more along the lines of you having purchased a "new" rifle that hadn't been broken in yet. Sounds like a great purchase!

 

[50Gunner]

Good stuff, fantastic rifle and cartridge, you may indeed be shooting the barrel in, or through shooting loosening that pesky forearm screw in the stock, every single one of my pre-64's shoot better with it removed, i keep them all oiled in their own little ziplock bags, your exact rifle is one i'm taking to The Limpopo this fall, it wears an old Lyman receiver peep sight and fires 220gr partitions over H-4831 powder, it will be a great light gun for my M-70 458 WM, have fun and enjoy that grand old cartridge.

 

[Vintageguy]

Good stuff, fantastic rifle and cartridge, you may indeed be shooting the barrel in, or through shooting loosening that pesky forearm screw in the stock, every single one of my pre-64's shoot better with it removed, i keep them all oiled in their own little ziplock bags, your exact rifle is one i'm taking to The Limpopo this fall, it wears an old Lyman receiver peep sight and fires 220gr partitions over H-4831 powder, it will be a great light gun for my M-70 458 WM, have fun and enjoy that grand old cartridge.

My favorite rifle is my old Winchester 54 in 30-06 with a Lyman peep. I have been seriously considering taking it over next trip for the plains game. Those old bolt guns with peep sights are the picture of classic.

 

[gbflyer]

Nice shooting. When I get one like that I like to put it back in the safe. Haha.

 

[shootist~]

Wow. IMO, continue whatever cleaning process as you have - it appears to be magical.

 

[ZG47]

Ok, here’s a brain teaser for your consideration. I bought a pre 64 Winchester model 70 in 300 H&H a few years back with the intent of taking it to Africa. I bought factory Hornady 180 grain ammo and shot it but my best groups were 1 1/4 inches. So I began working hand loads with various bullet weights,…the usual. But still groups of about an inch were it but nothing to be too excited about. Usually when I go to the range I typically take at least two guns and most days I could get really nice groups from the others but this one just ok. So I’m confident it wasn’t me.

Then a few months ago what you see attached started becoming fairly commonplace and it is shooting groups like this with factory loads and not just my hand loads. My only theory is despite the gun being made in 1955 the bore was never broken in. There was no copper visible in the rifling and it will spin a bore brush off my cleaning rod despite it’s having a free spinning handle. The only 30 cal rifle I have that will do this. Anyway, it’s bore’s rifling shines like a penny now. I haven’t had a rifle change like this without my knowing I caused it and how but I’d be interested in hearing your theories.

@Vintageguy There may have been sharp edges to the leade. The golden rule with a .22 long rifle is that you need to shoot at least 50 rounds through a brand new barrel before doing accuracy testing. An Anschuetz 1913 user might put 500 rounds through a new barrel before getting serious with data records. That is why you hold on to your less accurate .22 cartridges, to save wasting the good stuff. Rimfire and BPML barrel steel tends to be a bit softer than centrefire barrel steel because it needs to be nice and smooth for lead bullets.

Centrefire steel is harder and therefore you need to use cupronickel (gilding metal for velocities above 2,400 fps or so) jacketed bullets, to smooth those edges OR you could fire 50 to 100 cast lead bullets through a brand new barrel. Time, resources and patience are all factors in this process.

In my experience, a brand new or relatively new centrefire self-loading gas operated rifle will always deposit some jacket material on the gas plug. A worn in barrel will not (at least visibly) do so.
It is not the rifling, so much as it is the chambering and gas port drilling that create the issue. Less than perfect barrel steel may require a wee bit of shooting to fill the pores of the metal BUT the biggest accuracy effects appear, in my experience, to come from sharp edges of newly cut leades and newly drilled gas ports.

I am not a gunsmith but I have had the benefit of extremely useful conversations with excellent gunsmiths and other highly competent shooters who do (or did, in regard to those who are now deceased) some of did their own rifle building/modification.

It is worth noting that the cutting angle on a production line chamber reamer will typically be twice as steep as that on a gunsmith’s chamber reamer; and the cutting edges are likely to be somewhat more dull before that reamer is taken out for regrinding. The modern use of roughing reamers extends the useable life of what is now called a ‘finish reamer’ but a gunsmith’s centrefire chamber reamer might be used fewer than five (5) times before being reground. That is part of what you pay for, when you engage a true gunsmith to build a rifle, rechamber a barrel or fit and chamber a new barrel.

We are always learning and I try to pass on both the results of my own experience and useful information imparted to me by others. I have been privileged to interact with a number of highly talented, skilled and experienced shooters and gunsmiths. Many firearm users are not so fortunate, especially those who live in the back blocks OR in very large cities where use of outdoor ranges, game hunting, pest control etc. require long drives.
Great news about your bang stick. Hunting report to come?

 

[gbflyer]

Ok, here’s a brain teaser for your consideration. I bought a pre 64 Winchester model 70 in 300 H&H a few years back with the intent of taking it to Africa. I bought factory Hornady 180 grain ammo and shot it but my best groups were 1 1/4 inches. So I began working hand loads with various bullet weights,…the usual. But still groups of about an inch were it but nothing to be too excited about. Usually when I go to the range I typically take at least two guns and most days I could get really nice groups from the others but this one just ok. So I’m confident it wasn’t me.

@Vintageguy There may have been sharp edges to the leade. The golden rule with a .22 long rifle is that you need to shoot at least 50 rounds through a brand new barrel before doing accuracy testing. An Anschuetz 1913 user might put 500 rounds through a new barrel before getting serious with data records. That is why you hold on to your less accurate .22 cartridges, to save wasting the good stuff. Rimfire and BPML barrel steel tends to be a bit softer than centrefire barrel steel because it needs to be nice and smooth for lead bullets.

Centrefire steel is harder and therefore you need to use cupronickel (gilding metal for velocities above 2,400 fps or so) jacketed bullets, to smooth those edges OR you could fire 50 to 100 cast lead bullets through a brand new barrel. Time, resources and patience are all factors in this process.

In my experience, a brand new or relatively new centrefire self-loading gas operated rifle will always deposit some jacket material on the gas plug. A worn in barrel will not (at least visibly) do so.
It is not the rifling, so much as it is the chambering and gas port drilling that create the issue. Less than perfect barrel steel may require a wee bit of shooting to fill the pores of the metal BUT the biggest accuracy effects appear, in my experience, to come from sharp edges of newly cut leades and newly drilled gas ports.

I am not a gunsmith but I have had the benefit of extremely useful conversations with excellent gunsmiths and other highly competent shooters who do (or did, in regard to those who are now deceased) some of did their own rifle building/modification.

It is worth noting that the cutting angle on a production line chamber reamer will typically be twice as steep as that on a gunsmith’s chamber reamer; and the cutting edges are likely to be somewhat more dull before that reamer is taken out for regrinding. The modern use of roughing reamers extends the useable life of what is now called a ‘finish reamer’ but a gunsmith’s centrefire chamber reamer might be used fewer than five (5) times before being reground. That is part of what you pay for, when you engage a true gunsmith to build a rifle, rechamber a barrel or fit and chamber a new barrel.

We are always learning and I try to pass on both the results of my own experience and useful information imparted to me by others. I have been privileged to interact with a number of highly talented, skilled and experienced shooters and gunsmiths. Many firearm users are not so fortunate, especially those who live in the back blocks OR in very large cities where use of outdoor ranges, game hunting, pest control etc. require long drives.
Great news about your bang stick. Hunting report to come?

I’m not too sure about that reamer information. 5 times? Been my experience that I get a better chamber with one after 3-4. Only ones I’ve ever had trouble with are razor sharp brand new ones.

 

[Racinjason]

I’m not too sure about that reamer information. 5 times? Been my experience that I get a better chamber with one after 3-4. Only ones I’ve ever had trouble with are razor sharp brand new ones.

As the reamers get used the tolerances change and the chambers are not as perfect.
Some cartridges you can get away with multiple chamberings (ie 600 overkill, 500 nitro etc), but your bottleneck cartridges that remove a lot more material wear down quite quickly and if one wants to hold tight tolerances for custom high dollar rifles, 5 chamberings is about the number to be safe. Box store companies like Remington, Winchester, Savage and whoever else can get away with reaming tons of rifles before re sharpening a reamer I would imagine because they aren't worried about holding the upmost of tolerances. Those rifles still shoot fine for the average person, but when you pay thousands of dollars for a custom rifle, you tend to expect more.

 

[ZG47]

@gbflyer Thank you for responding. I make no claims to be a gunsmith but I know what you mean about brand new cutting tools sometimes being a bit tricky to use on the first few cuts.

The conversation which brought up the issue of reamer sharpening was with an older friend who passed away some years ago. I suspect that he did most of his clambering work before roughing readers became relatively common and he might also have been recalling some particularly hard barrel steels.

It should also be borne in mind that he was a Ballinger Belt winner who rebarrelled multiple NRA target rifles and was often the first choice gunsmith for someone building a special hunting rifle. I recall reading a series of articles published in NZ Guns magazine by Carl Rofe, who had a Brno ZKW 465 barrel bored out and rerifled, in order to create a .30 Carbine bolt-action repeater. The man who did the boring and recutting of the rifling reportedly stated to Carl that the steel came out of the barrel in chips.

All of the above factors come into play with reamer life. Have a good week.

 

[CBH Australia]

All that practice paid off.

 

[TMac]

Easy answer. All rifles are female. Their preferences change on a whim, you never know what to expect, and if you think you know what they want they will change, etc. etc. etc.

I have a favored rifle that has changed what it likes/does twice. My best guess, throat wearberosion changes it’s preferred loads, one reason some competitors chase it every 100-200 rounds with bullet seating depth.

 

[gbflyer]

@gbflyer Thank you for responding. I make no claims to be a gunsmith but I know what you mean about brand new cutting tools sometimes being a bit tricky to use on the first few cuts.

The conversation which brought up the issue of reamer sharpening was with an older friend who passed away some years ago. I suspect that he did most of his clambering work before roughing readers became relatively common and he might also have been recalling some particularly hard barrel steels.

It should also be borne in mind that he was a Ballinger Belt winner who rebarrelled multiple NRA target rifles and was often the first choice gunsmith for someone building a special hunting rifle. I recall reading a series of articles published in NZ Guns magazine by Carl Rofe, who had a Brno ZKW 465 barrel bored out and rerifled, in order to create a .30 Carbine bolt-action repeater. The man who did the boring and recutting of the rifling reportedly stated to Carl that the steel came out of the barrel in chips.

All of the above factors come into play with reamer life. Have a good week.

That’s a good bit of info. Thanks.

I’m no gunsmith either. I am a very enthusiastic hobbyist with a lot of tools a real gunsmith would drool over though. I can’t say that I can tell any difference from a reamer I’ve used once or a dozen times in terms of accuracy. And yes I have made one tomato stake in my tenure, with a rented .22-250 reamer that I could not for the life of me beat the chatter. Glad it was a used barrel. There are a million ways to make a reamer follow a hole, and everyone’s way is the right way, lol. I don’t make my own barrels so I am pinned to the quality of who’s ever blank I am using.

At any rate, glad that .300 is shooting well for the OP. Lots of good and bad juju going on inside that steel pipe.

 

[Shootist43]

Another possibility is that your current ammo's velocity is at an accuracy node.

 

[willbaforce]

You broke it in and all the practice paid off.

 

[Racinjason]

That’s a good bit of info. Thanks.

I’m no gunsmith either. I am a very enthusiastic hobbyist with a lot of tools a real gunsmith would drool over though. I can’t say that I can tell any difference from a reamer I’ve used once or a dozen times in terms of accuracy. And yes I have made one tomato stake in my tenure, with a rented .22-250 reamer that I could not for the life of me beat the chatter. Glad it was a used barrel. There are a million ways to make a reamer follow a hole, and everyone’s way is the right way, lol. I don’t make my own barrels so I am pinned to the quality of who’s ever blank I am using.

At any rate, glad that .300 is shooting well for the OP. Lots of good and bad juju going on inside that steel pipe.

The fact that it was a used barrel and on such a hot cartridge, the steel hardened up. A lot of gunsmiths either won't rechamber a rifle that has been fired or they will only do it if it hasn't been shot but a few times because of this.

 

[BryceM]

Ha. My old trusty .300 Weatherby Mk V started doing that 20 years after I bought it -- when I actually LEARNED HOW TO SHOOT IT.

As far as your rifle, you're probably right about the breaking-in issue, but who cares? Don't ask too many questions.

 

[csmiffy]

yeah, I officially hate you lol.
Very jealous. If I ever get one of my long-suffering projects done (hopefully a 300 H+H if I can find a reamer, on a sporter p14) and it shoots like that I will be ecstatic,
Nice one

 

[rookhawk]

Did you disassemble the gun? Taking a gun out of its stock could have removed a piece of debris effecting harmonics or the torque on the bottom bolts could have been off.

 

[Vintageguy]

Did you disassemble the gun? Taking a gun out of its stock could have removed a piece of debris effecting harmonics or the torque on the bottom bolts could have been off.

I did when I first got it as I do on every gun new or used but haven’t since I started shooting it.