Barrel bore size

[homebrew .357]

Hi, As I`m into making my own barrels would like to know the size of a .50cal black powder barrel bore. Is it .500" and then the cut rifling to .007'-.010 deep, or is it .500 after rifling. Just trying to get an idea of the gun drill size one would use for a .50cal barrel, .488" then rifling, my Hawken bore is .457", I used a .444" drill. thanks, Homebrew.357.

 

[okawbow]

A .50 caliber is usually drilled a little under .500, then reamed to .500, then rifled with grooves anywhere from .005" deep to as much as .020" deep. I like about .012" myself.

In the real world, most bores are drilled, then reamed until a perfect finish is achieved. Then rifled. They might be anything from .495 to .505 and still be called a 50 caliber. That's why it's always a good idea to push a lead slug through the bore, and measure the land diameter and groove diameter so you know what you have, and what patch thickness is needed.

 

[homebrew .357]

Thanks for your reply, now know that drill to look for, have already made two rifles, first one is a Hawken plains kiwi rifle, to see the build go to WWW" You can't make rifle barrels on a lathe" I will not say what the other one is, more moden and not allowed on here. :nono: Homebrew.357.

 

[tenngun]

In the old days guns were made to so many ball to the pound. While there were standard calibers we find a lot of guns listed today as .51,.47..49ect back then they were all 38 bores. J&S Hawken are often listed at.53 for their 32 bore gun.

 

[homebrew .357]

Ok, I now have a .50cal rifled 8 groves, about .010" deep and 21" long. Will give it a good lead Lapping to Finnish the bore. I know its a short barrel but there you go, so what would be a starting load with p r b and 2f, I`m looking at using it for deer hunting. Homebrew.357.

 

[BrownBear]

Based on other barrels in the 20-24" range, I'd sure try 3f in your barrel as well as 2f. My short barrels have always performed better with 3f, plus they're not nearly so noisy.

You never mention your twist rate, but my usual 50 cal load for deer is 80 grains of 3f or 90 grains of 2f. That's more than enough for deer and less will work, but I use those charges to get the trajectory I want.

 

[Grenadier1758]

With your barrel in a rifle, its now time for load development.

I have to go with general statements here. A starting load of 55 grains (volume measure) of 3 fg powder would be my starting load and a 0.017" dry lubed drill cloth patch wrapped around a 0.495" ball. Increase the charge 5 grains after firing a 5 shot group. You are looking for tightest group. With short barrels once you get past 75 to 80 grains you will increase muzzle blast, recoil and gain little in velocity.

 

[homebrew .357]

OK,First it is a 1-48" twist, this seams to be the rule of the thumb for ball and bullet, second I`m lapping the bore and then I will thread and fit the breach plug, cut it octagonal and sight slots . Then a good finish sand and rust brown to look the part. I agree with 3f for the short barrel to get a good powder burn and when ready to shoot will slug the bore to see what size I've got and patch the ball for a slight tight fit, all good fun. Cheers, Homebrew.357.

 

[Rifleman1776]

I dunno 'bout that.
Short barreled rifles, to me, are always noisy. My wife had a H&A buggy rifle that was loud, loud, loud. Especially under a covered firing range. Real boomer. I've shot some short barreled shotguns (20" to 22") and they were real ear blasters. Methinks the effect is simply that the muzzle is closer to the ears than with longer barrels. Dunno. :idunno: I still wear hearing protection.

 

[tenngun]

Today many of our guns run in the 1/60 something out to 1/72. 1/66 being common. In the old days 1/48 was common long before conicals became common. A 1/48 will shoot round ball just fine.

 

[Col. Batguano]

I think that's part of it. A 44" barrel is usually 5-7 dB quieter than a 40" one at the shooter's ears, but it's also a function of the expanding gasses. BP gasses expand more slowly than smokeless, or ultra fast stuff, like TNT.
Lower muzzle pressure produces a lower amplitude shock wave, and the larger the caliber, the lower the pitch of the sound. Higher pitch sound seems to be more painful than lower pitch too. Big weapons even when they make a low pitch can be harmful too. Think about an artillery piece. Though loud, the concussion of them is quite notable as well. If you're close enough to them, they can even disrupt internal organs. That's why bomb blast victims often appear to have no marks on them.

 

[homebrew .357]

Well not to worried about the bang it makes, you must all ways wear earmuffs at the range and when hunting it`s only one bang and that's it, you the have to worry about getting it out of the bush and steaks or hotpot for dinner, that's if you hit it. :thumbsup:

 

[BrownBear]

Well not to worried about the bang it makes....

Speaking from first hand experience with short barrels and large charges, enjoy the consternation it causes among your mates at the range! My short 58 caliber is so loud, my buddies have named it Dang!!!!, and they all move back from the line a little when I unlimber it. But they all want a turn shooting it as well! :thumbsup:

 

[Rifleman1776]

Well not to worried about the bang it makes, you must all ways wear earmuffs at the range and when hunting it`s only one bang and that's it, you the have to worry about getting it out of the bush and steaks or hotpot for dinner, that's if you hit it. :thumbsup:

Agreed and good info. I have long wanted a set of those electronic ear plugs that allow normal sounds but shut off for loud. But, they are expensive.