1903

[cptjack]

1942 edition 03 slugged bore .miced .310 ,but fell out before reaching the chamber assuming throat is eroded,so is barrel shot out......swag bullit .311? thanks

[gnoahhh]

One way to find out- shoot it.

On the other hand, a chamber cast to include an inch of the throat will tell the tale also.

[6.5 mike]

Measure the ID of a fired case, it will tell you how big a boolit you'll need to fill the throat. My REM 03 needs 0.315.

[Ballistics in Scotland]

It depends what you mean by "just before, but military rifles often do perform rather well with the combination of lengthened throat and slightly oversized bore. The choice of bullet is likely to be important. Something like a solid based boat tail is likely to perform poorly when bullets with simple and fairly soft jackets are fine.

[sghart3578]

I have a 1903 of the same vintage that also slugs at .310". My bore seems to be the same all the way through.

I cast a Lee 312-185, gas check and size to .312". Works beautifully.

I also tested a few NOE 311284's sized to .312" and they were also excellent. The were given to me and now I am waiting for NOE to cut this mold again as they are presently out of stock.

Best of luck.

[gnoahhh]

Measure the ID of a fired case, it will tell you how big a boolit you'll need to fill the throat. My REM 03 needs 0.315.


I may be overlooking something but how does the ID of a fired case correspond universally to throat diameter? In my "go to" '03, a .309 bullet will just barely enter a fired GI LC-69 case, a .310 won't. Yet I know it has a .310 throat because I made it that way when I re-throated the original leade with a 1½º included angle throating reamer w/ .310diameter throat included. (It had a .309" throat to begin with.)

I did that because I wanted to shoot heavy long bullets in it. I took things a step further and made an "Ardito die" reamed with the same throating reamer in which I swage the noses of the cast bullets (various 200-220 grain long nose bearing designs) to conform to the new throat. This allows me to seat them way out, and accuracy is is the best I ever had with an '03 in military configuration. It precludes magazine loading (cartridges are now too long), but that's a small sacrifice to me- I'm not planning on any rapid fire matches, hunting, or zombie killing with it. Bases remain as-cast at .310" for a snug fit in the throat.

Caveat: it is a new Criterion barrel with otherwise standard arsenal dimensions, .300 bore diameter and .308 groove diameter.

Magazine fed "normal" cartridges with lighter cast bullets still offer darned good accuracy to boot anyway. But that may be due to the fact that I'm anal about making my cartridges as straight as possible with minimal runout. (I think that is an aspect of loading cast bullets that is overlooked by a lot of guys as they stress over bullet design and diameters. No matter how well a bullet is made to fit its barrel, it's all for naught if it starts into the rifling crooked anyway.)

My conclusion: it boils down to a sort of which came first the chicken or the egg kind of thing. Either one matches his bullet selection to the throat he has, no matter what its dimensions, or one makes his throat conform to the bullet he wishes to shoot.

[Char-Gar]

You have no problems. Size your bullets .311 and/or .312 load and shoot. Unless the bore if pitted like a water pipe, you will get good results.

Forget about the ID of a fired case and even slugging the bore of your rifle. The diameter of the barrel throat is the only dimension that matters.

[Char-Gar]

Measure the ID of a fired case, it will tell you how big a boolit you'll need to fill the throat. My REM 03 needs 0.315.

The ID of a fired case will tell you nothing about the throat of a rifle. The case neck expands to filled the neck of the chamber and then bounces back a smidge the allow the case to be extracted. The ID of the fired case will tell you, how big a bullet you can shoot in the rifle without encountering chambering issues and nothing more. The throat is in front of the chamber neck.

I don't know how this nonsense gets started, but once it does, it picks up speed pretty fast.

[sundog]

The ID of a fired case will tell you nothing about the throat of a rifle. The case neck expands to filled the neck of the chamber and then bounces back a smidge the allow the case to be extracted. The ID of the fired case will tell you, how big a bullet you can shoot in the rifle without encountering chambering issues and nothing more. The throat is in front of the chamber neck.

I don't know how this nonsense gets started, but once it does, it picks up speed pretty fast.

Yup, not only that but there is a vast range of neck thicknesses to contend with. If your chamber is otherwise uniform and concentric, use brass with uniform neck thickness (neck turn if need be) and load the largest diameter cast boolit that will chamber without forcing it.

[gnoahhh]

Forget about the ID of a fired case and even slugging the bore of your rifle. The diameter of the barrel throat is the only dimension that matters.


I thought of saying that, but assumed that by now everybody knew that. I know, don't assume a darned thing...

[Char-Gar]

I thought of saying that, but assumed that by now everybody knew that. I know, don't assume a darned thing...

If seems like there is no memory on this board and the wheel must be reinvented every six months or so. Somebody will put up an ill informed post and it will get repeated over and over again until a new myth/old wives tale is born. You can try and drive a stake through the heart of the things, but that doesn't work. Neither does silver bullets or garlic.

The problem is that new people to this board can't distinguish between the people who actually know what they are talking about and those that only act like they know what they are talking about.

[Char-Gar]

The 30-06 round holds no secrets when it comes to what size cast bullets to use. The code was broken on this generations ago.

With a commercial rifle, .310 is a good choice. .309 might work a smidge better on some rifles with very tight specs.

With a USGI (1903, 1917, 1903A3)rifle, .310 is good for a pristine barrel. .311 if the barrel has been to the range many times. .312 if the barrel has a worn throat from long term usage.

It is not unusual to encounter a USGI rifle with .309 - .310 land diameter in those made during war time. That said, the above specs will catch even those.

Now Krag rifles are a different critter. There can be as much as 7 thou difference in land diameters. They also have very large and long throats and .313 or even a smidge larger will give good results in most Krag barrels.

Note to captjack: If you push a lead slug down the barrel of any rifle with a throat, it will fall free before it hits the chamber because even an unworn throat is larger than the land diameter of the barrel. So dont draw and conclusion from that fact.

[Char-Gar]

Yup, not only that but there is a vast range of neck thicknesses to contend with. If your chamber is otherwise uniform and concentric, use brass with uniform neck thickness (neck turn if need be) and load the largest diameter cast boolit that will chamber without forcing it.

That works unless you have a large chamber neck that will take a bullet larger than the throat. Then you will shave lead on the rear edge of the throat, which is not a good thing. Of course this depends on the bullets. A long bullets that enters the throat will balk once the bullet gets to large and a chambered dummy round will show the lead shaving.

[cptjack]

thanks to all upset about buying a shot out firearm, went to range today with 10 reloads 55 gr 4350 over 165 gr hdy sp all over the place, next 46 gr 4350 over 165 gr sgk now I have a 1 1 /2 group so has potential

[NavyVet1959]

Note to captjack: If you push a lead slug down the barrel of any rifle with a throat, it will fall free before it hits the chamber because even an unworn throat is larger than the land diameter of the barrel. So dont draw and conclusion from that fact.

I always figured that barrels should decrease in diameter between the chamber and the muzzle. Maybe not the entire length, but over enough of a distance that it can more easily resize the bullet to the final diameter. I would be more concerned if I was pushing the lead from the chamber to the muzzle and then it decides to fall out before it gets to the muzzle. By slugging a barrel from the muzzle end, I would think that you might not notice a barrel that starts to open up before it gets to the muzzle.

[gnoahhh]

Making a choked (tapered) rifle bore is very problematic and not done except by a very few custom barrel makers over the years.

OP- I didn't see anyone upset that you bought a shot out barrel! Glad to see the accuracy you're getting. All of our comments were directed at it's utility as a cast bullet shooter though (a natural assumption as this being a cast oriented forum).

[Char-Gar]

Making a choked (tapered) rifle bore is very problematic and not done except by a very few custom barrel makers over the years.

OP- I didn't see anyone upset that you bought a shot out barrel! Glad to see the accuracy you're getting. All of our comments were directed at it's utility as a cast bullet shooter though (a natural assumption as this being a cast oriented forum).

Yea, I read that as well. Looking at his post, looks like it was sent from a hand held device and he was trying to use a few words as possible. In this case, he missed some important words....I think. I thinks HE was upset, but now sees some hope.

[NavyVet1959]

Making a choked (tapered) rifle bore is very problematic and not done except by a very few custom barrel makers over the years.


But ideally, it should taper towards the muzzle, not towards some midpoint in the barrel and then open back up, right?

I would think that to create a tapered rifle bore the method would be to create a rifled mandrel and then hammer forging the barrel around the tapered mandrel. Pretty high startup costs compared to button rifling though.

[Scharfschuetze]

An interesting aside is the German's use of tapered bores in anti-tank rifles and light anti-tank cannons. I believe it was called the Gerlich system after one of the designers. It was not developed for accuracy, but to maintain high pressure on the projectile all the way to the muzzle. The rifle version tapered to 7mm at the muzzle and achieved a muzzle velocity of something like 5,900 fps or 1,800 mps.

Unlike us shooting lead, these rifles shot a tungsten cored projectile with collapsing skirts, but the lack of this metal in WWII Germany precluded the widespread use of the weapons. Having made a few barrels on button rifling machines, I've always wondered how they made the barrels with their extreme taper.

Back to the report of the lack of uniformity in the OP's barrel. I think that you are better off with the larger diameter at the throat. This is quite common with well used rifles and I have an actual armorer's gauge to measure this wear in the 1903. You should be able to overcome it easily by sizing your boolits slightly over the diameter of your throat. I have a circa 1915 1903 with a good bore, but a worn throat and it shoots just fine with boolit's sized to .002" over the initial diameter of the barrel. I use the Lyman's 314299 mould for this rifle and it shoots quite well.

[NavyVet1959]

I believe that Glock uses the hammer forging on their polygonal rifled barrels. It supposedly is very quick as compared to cut type rifling, but had a high initial machine investment startup costs, but the barrels can be produced cheaper. So, if a company is making a LOT of barrels, they can recoup their investment. Smaller companies, are stuck with button / cut rifling. I believe that the mandrel is not limited to polygonal rifling though. They should be able to cut mandrel that is a positive image of a cut rifling barrel and then hammer forge the steel around it to create the barrel. Removing the mandrel would basically be unscrewing it from the rifling (screw threads) of the newly created barrel. As such, the same procedure could be used for a tapered mandrel. On the other hand, I'm not so certain that a progressive twist rifling could be made via hammer forging. I think that would need the traditional cut / button rifling and the machine would need to vary the rotation of the barrel as the cutter progresses down the length of the barrel.

[Ballistics in Scotland]

Hermann Gerlich came over to do some development work for Winchester, and they found that his squeeze bore principle didn't give quite the velocities hoped for, and not enough to justify the increased cost, and possibility the chance of faults creeping in during manufacture. It did see use as a wartime German anti-tank gun, which was good, but not good enough to stay in production along with more easily made straight-bore versions. At a guess, the barrels were probably reamed as tapered smoothbores, with an expensive special reamer, and hammer rifled. I don't see any way of accurately cutting or broaching such rifling.

Ever since the muzzle-loading days there have been attempts to make the bore tighten up on the bullet to a much slighter extent, probably achieved by lapping. It would compensate for wear on the bullet, although I believe the original aim was to reduce the effect of black powder fouling on loading, since it is mostly deposited close to the breach.

Gain twist rifling of course can't be produced by hammering or swaging onto a mandrel, as you could never get it out again. I also doubt whether button rifling is a good way of doing it. Modern button rifling processes usually rotate the button by means of the rod, in a manner simple to cut rifling, but there is a lot of torsional elasticity in a rod suitable for a smallbore barrel. I would only trust it to achieve a consistent twist rate if the turning rod backs up a spiral image of the rifling which is also cut in the button. As that can only be a constant spiral, a gain twist barrel would require a button rotated only by the rifling rod, and liable to change its pitch in its and starts.

It is indeed a good idea to slug a barrel from both ends, and probably both with fresh slugs and one which has had already had the rifling engraved in its first trip along the bore. I don't think a reducing bore diameter is worth going to any trouble for, but it would at the worst be harmless if the taper is only a thousandth or two. It is a widening barrel that is really harmful.

It isn't true that a groove diameter two or three thousandths over specification is always harmless, although very often it will prove so, especially with cast bullets - although in this case I would prefer to use bullets which are either patched or without a sharp rear edge, to reduce finning. I once tested a .303 barrel which I was about to replace, with several near-exhausted boxes of .308 bullets. The bore was frosted but not pitted, and the throat was close to the way it was made. I got good accuracy with fairly thin, sheet copper jackets, but Nosler solid based boat-tails didn't expand to seal the bore, and mostly keyholed. I found recovered bullets to be engraved with the riflng to full depth on one side, and not at all on the other. If a bullet doesn't expand enough to centre itself immediately, it gets slightly off-center, and slightly turns into a lot as it is pressed against one side of the bore by centrifugal force.

I once tried to spin about three inches of spring tempered 1/16in. piano wire in a Dremel tool, and it immediately bent over sharply just outside the chuck. (Memo to self: Do not try this with anything brittle. Do not try it again with piano wire, in fact.) But a .303 bull spins over six times faster. Don't underestimate centrifugal force.