doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Barrels thickness for Bk Powder

Hello.
For twisted, damascus or even steel where what should be the thickness for barrel intended to be used with black powder, where to check it ?
thank you

There is no difference between the requirements for BP and nitro powder.

Rocketman is right, there really is no difference between powders--pressure is pressure. However, there is a huge variation in barrel thickness, especially near the breech. Some guns were made for light loads and are quite thin. Others designed for heavy waterfowl have breeches that seem to have been intended for cannon shells. So, barrel thickness and tapers are directly related to what the intended use was. Main caveat is to be wary of using heavy loads in guns that appear to have lightweight barrels. If you don't have enough experience to make a educated judgement about the barrels this is a great time to have a qualified gunsmith to take a look at them for you.

While there are exceptions to all rules, it has been my observation that many guns built prior to the introduction of smokeless powder had thinner walls over the chamber area. While the thickness at end of chamber itself may not have been that different many of these early guns have less taper to the OD & thus are of a smaller dia at breech face. Max pressures have traditionally been taken at 1" from breech which is said to be far enough to catch max with any normal shotshell load. Most early smokeless powders, both dense & bulk, were faster burning than BP, thus if loaded to same ballistics they gave a higher breech pressure than did black. With the introduction of smokeless the breech area of the bbls began to be beefed up, not 12-14"s down the bbls in spite of many old wife tales of higher pressures there. While I shoot most of twist & damascus guns with either black or moderate pressure smokeless loads, these early guns having very light breeches I personally reserve strictly for black.

I'm confused (very easily done). If "pressure is pressure" and there is no difference then why not shoot smokless low pressure loads and not have the other cleaning issues (and others) that come with BP? I've got a Winchester 1893 12b that I am planning to shoot BP through. Could I shoot low pressure smokless through it as well? I was sticking with BP, due to the gun being made/designed for BP. This model has also had a history of not being able to hold up to the switch to smokless powder. Hence the introduction of the new and improved Winchester 1897. I guess I was under the assumption that BP always produced lower pressures.

2-p is correct that "pressure is pressure." Black powder does not produce the low pressure some people imagine. It is very easy to load or (now) buy loads of known low pressure - actually lower than the BP. The main issue with early nitro powders was that controlling burn rate was not well understood. It was easily possible to overload shells. Also, there was a race to make high velocity loads and some of the older guns were not up to the newly possible pressures. Nitro got an across the board bad rap.

Some peole just plain enjoy BP with all its needs. Others can benefit greatly in the shooting of older guns with appropriate nitro loads and the reduction in needs. If you can shoot a cartridge gun with BP, it is possible to shoot it safely with nitro. The key is to fully inform yourself before you pull the trigger the first time. If you don't know it is safe, don't do it. Period. If you hesitate to shoot a gun with nitro, hesitate equally to shoot BP. Fortunately, there is a world of information availabel in this time.

Ironman5,

Don't worry. You would not be the 1st to be confused. There are all sorts of reports about barrels bursting while shooting black powder. The proof houses regularly had barrels burst. It was one of the driving forces behind Damascus development and the search for better fluid steel manufacture.

I am not sure that barrel thickness is the only factor. There were various qualities of Damascus and fluid steel around. Some fluid tubes were dangerous as were some Damascus barrels. I believe the quality of the barrel plays a role.

Measuring thickness and developing safe loads are part of the process. The other is having some one with knowledge to give advice.

Many years ago, I pickup an old Ithaca with Damascus barrels. They looked fine to me. To be sure, I sent them to Oscar Gaddy. When Oscar got the barrels, he gave me a call. He pronouced them unsafe at any pressure. He could see defects in the tubes. With out his sage advice I might be minus a digit or two. He marked the defects and sent them back. We spent some time on the phone so that Oscar could educate me.

Pete

Ironman, most of my doubles are damascus and were made before nitro powders came on the scene. Though I have shot black powder for over 50 years in muzzleloaders I just don't like it in doubles, especially when a quick second shot is needed. And black powder burns incredibly hot, uncomfortably heating the barrels in rapid shooting. So, virtually all of my shooting is with low pressure nitro powders concocted to render pressures which nearly duplicate black. This is easy to accomplish and the neat thing is you do not need to sacrifice ideal velocities--around 1150 to 1200 fps. With such loads the gun's softer metals are not overly stressed, and best of all, recoil is much gentler.

Low pressure ammunition (I prefer to call it "reasonably pressured" in contrast to the American mantra for magnum) can be bought over the counter. RST, Federal and Winchester all offer the lighter loadings that should be satisfactory.

Reloading is probably the most versatile way to go and many load recipes can be found which produce the desired velocities with under 7,000 psi. Sherman Bell wrote four articles in the Double Gun Journal about shooting low pressure nitro in these old guns and I sure recommend your beginning the journey by purchasing these copies: Volume 10, issue 2 (1999); Volume 10, issue 4 (1999); Volume 12, issue 4 (2001); and, Volume 13, issue 2 (2002). You'll also find an article on the pressure effects of shooting 2 3/4" hulls in short chambers.

Good luck in your journey!

Let me clarify a point or two which may not apply to all concerned. The majority of the damascus/twist guns I shoot were made after about 1890 & have heavier breeches than some of the earlier guns I mentioned. Most of these guns were listed by their makers as being suitable for smokeless powder. These guns I shoot with either black or smokeless as my mood dictates. Also I have no qualms about using shells loaded in the 7500/8000 psi range with these guns. Now it is true you can find light load data in the 4-5K psi range in 12ga. These loads will universally be found in the "Target" load section. I have never been a high volume competive shooter. Most of my shooting has always been hunting with some clays for practise, mostly from a "Cow-Pasture" thrower set-up. Those early guns I mentioned may be carried out for an occasional hunt, & as I fire up the "Explorer" the temp indicator above the windshield may be flashing "Freezing". I do not trust Smokeless below about 7.5K under these conditions, black I do. A black powder breech-loading shotgun is quite easy to clean.

How does the ambient temperature effect/affect the dependability of low pressure smokeless loads? And secondly, how does it NOT effect black powder?

I have always read that cleaning doubleguns shot with BP was easy. Just remove barrels and flush with hot water thouroughly and coat with your favorite protectant. Is that accurate? If so, how do you clean a pump gun properly if the barrel isn't removable? Pour the hot H2O in from the breech?

Joe, Thanks for the reference to the DGJ back issues. Can they be purchased off of this board? This topic fascinates me to no end. I have several guns 100+ years old so this info is definetly a subject I want to know about. Once I learn enough about it... I'm afraid they'll outlaw lead all together and then all the useable loads will be obsolete.