That I finished the test bed shop gun, was that it was developed to be able to readily accept almost any barrel ( with appropriate prepared hub interface).

Folks seem to have such an aversion to preparing their own ammo - I thought I'd make it possible to test a commercial barrel or two. Thing has always been a catch 22. I can't make a cheapo gun. So; when someone buys a Barnes with a commercial barrel on it, and shoots some old crap slugs they found in box format ... and it works poorly, who gets blamed?

Twice, in the past; I've designed barrel series for slugs that then disappeared off the market. Nutz. But - tell me if you know if barrel slug combinations that are being used to good effect. I don't mean to suggest that I'm the only one that can make a barrel. My point is that I test my stuff and develop a slug (and the tooling to make it) that has been proven in the gun - by myself - at the range. I know it works.

If similar field work is producing good results on big bore - let me know. Might be a good thread of discussion.

I know that "barrel liners" are good products, due to their lower overall mass. That smaller mass is all that's needed on airgun power plants. But the rifling profile and twist rates have to be usable.

Think its a decent idea? With the slide breech (which I've come to like because it moves the breech forward, and has no bolt to move rearward - it lends itself to an occasional shooter who just could forget to close the breech well. And - it allows the breech to be removed with the barrel. You can thus; have a rack of barrels, each with the attached slide breech - that just thread onto the power plant - via the appropriate hub. Many calibers also will have the same size exterior diameter. Such as - for me; many of my 25, 308, 8mm, 32, and 38 caliber barrels are the same exterior diameter. So; they would all use the same hub and COULD use the same breech slide cover.

Anybody had good luck with this, or have a Bud that did?

Gary



Edited 2 time(s). Last edit at 01/29/2014 02:49AM by barnespneumatic.

The ammo really is the key, isn't it?

With airguns you just don't have the pressure to engrave copper jacketed rounds or full-bore-diameter lead slugs with long, parallel shanks, not and have any 'push' left to get the slug heading downrange at a reasonable velocity. Even with "high" pressure air, you're still only working with about 3000 psi, versus tens of thousands of PSI for cartridges with smokeless powder. All of your best slugs seem to feature multiple driving bands of the correct diameter and spacing to engage the (relatively shallow) airgun barrel rifling just so, not too loose, not too tight, just right. The slugs also have to have the right center of mass to keep from tumbling too soon (after impact is fine) and have a reasonable shape to facilitate loading and handling without being damaged. Most of all, they have to be consistent; consistent in mass, diameter, softness/hardness (not hard alloys like centerfire bullets), shape (for aerodynamics), eccentricity (for gyroscopic factors), and especially consistent in how they exit the muzzle since that drastically affects accuracy.

Speaking with some limited experience (I know, I know, I need to do a LOT more shooting) I can tell you that your .308 barrel insert will digest almost anything of reasonable diameter (and some not so reasonable, like .311, oops), but even with commercially available (not Jerrys) slugs of supposedly identical diameter some rounds "chamber" very differently from others. Some slip way down in, some snug right near the port. I haven't shot enough to figure which it likes the best, that's coming when the weather improves and I get some critical house-related projects finished. What I really need to do is just buy a chronograph and do some serious bench work, figure out which it likes and which it doesn't, buy that mold and stick with it.

I suspect that the commonly available cast-lead bullets for centerfire cartridge reloading are not going to be the ideal match for a .308 airgun barrel; the alloy is too hard, the critical diameter isn't consistent enough, and I just don't think that the usual bullet designs are ideal for airgun pressures and airgun rifling profiles. There might be a design out there which turns out to work great, but even if I do find it the batch-to-batch consistency is likely to be inadequate for best accuracy in airguns. Keep in mind that most cast-lead bullets in .308 diameter are sold to people who are trying to keep down reloading costs, not to benchrest or target shooters. In the centerfire rifle cartridge world the most accurate bullets are always jacketed, because at centerfire velocity any cast lead bullet, no matter how hard, will smear molten lead all down the bore. There are some exceptions, such as black-powder metallic cartridge shooting and target pistol loads like .38 Spl wadcutters, but those are much lower velocity compared to most centerfire shooting. The requirement list for the perfect airgun bullet somewhat overlaps what's typically available for centerfire reloading, but not exactly.

I think that if the desire is to find an airgun barrel bore diameter that will accommodate commercially available cast lead bullets with best accuracy in mind you might have to focus on the bore diameters and the bullets used in either blackpowder metallic cartridge silhouette shooting, or the low-velocity target pistol rounds like .38 Spl wadcutters. Those bullets are made to be accurate, not just cheap, and the market has weeded out that ones that just don't have the needed consistency. Otherwise, if you want excellent accuracy (and who doesn't?) we, as big-bore airgun shooters, are just gonna have to keep "rolling our own", so to speak. Custom slug designs, custom molds, custom built to accommodate airguns unique requirements. You've proven that it works, even if it is a bit inconvenient compared to just buying your ammo "off the shelf" at WallyMartWorld.

Hi Sean,

First item that stuck was that the commercial chamber differently - round to round. As you realize - the barrel doesn't change between rounds - so it's the perfections that come with a box of bullets dumped in a pile and shipped to Alaska. Just a dent or small flashing on a slug will hang it up. The cure is to run them all thru a hand sizer. Even if they are supposed to be 308 and you run them thru a 308 die. Almost no resistance - but it will take off the swells from dents or a flashing of lead.

You will wAntnto look at pistol bullets. Yes. Those are lead and of a weight appropriate for airguns.

Recall that I also told you that you can run common .310" lead ball thru your barrel.

You can get away with hard lead bullets if you just run them more shallow. Try 307- even 306. Of course - you have to size them.

Part of the conflict comes from modern vs. classic lifestyle. Part of the hobby of shooting is preparing and exploring our ammo. Modern hobby says that is not fun, and we expect to zip open a box, shoot a 1/4 MOA target, throw the whole mess in the trunk, and be back home in 1/2 an hour. Airguns are closer to fly fishing - where you tie your flies.

And so;I do believe that even a commercial barrel and box ammo will require a bit of "quality control" on the part of a shooter who wants good results.



Gary

Good points all, Gary. A sizing die setup is definitely in my future, and I'm going to have to widen my search for .308 slug designs. I'll definitely check out the "pistol" slugs, not just the ones designate for "rifle" in the catalogs.

This may be stating the obvious, but shooting a big-bore really is different from the usual airgun routine. You can't go into it with the mindset that there's going to be a couple dozen different slug designs just sitting on a shelf somewhere and you'll just grab a couple hundred each and try them all in one sitting. There's going to be some work involved if we want good accuracy shooting something other than what you've already worked up with the guns before you ship them. Thinking about it gives me a new appreciation for the time and effort you spend working out the best load/PSI combinations before you send them out.

It also points out that how fortunate we are in having such a wide selection of super-high quality pellets available to support our hobby when we shoot smallbore airguns, and for very affordable prices too. The level of precision involved in manufacturing airgun pellets is vastly superior to what you find when buying cast-lead bullets in bulk, night and day difference, really. The .308 bullets that I've found on the shelves here are pretty cruddy looking sitting next to the little gems that Jerrys boys turn out too, the level of quality control his guys (guy, singular now?) turn out are mighty fine by comparison.

Even Jerrys most expensive slugs are dirt-cheap compared to shooting centerfire rifle (or even .22LR these days ) I was looking for some ammo yesterday at one of the local stores and just about had a stroke when I saw a box of .375 Weatherby with a $168 price tag on it...for twenty rounds! Admittedly it was some pretty premium, exotic stuff, but still... over eight bucks a shot?

Hi Sean,

Guess you can define "Infinity" as an endless string of whole numbers .... OR .... You can divide "1" indefinitely. Haha.

If you don't have an infinite variety of slugs to try ... Guess you can use your one great slug and apply it to an infinite variety of different targets!

Besides ... You have a shotgun too, in that beast. Load the 308s you don't like as buckshot in the 62 bore. Haha.

Gary

Yeah, use Gary's trick, hold the barrel about halfway down and pour lead in until it seems about even with the hand holding the barrel. No math! But you have to video the shot where you destroy the entire range!

Brilliant! I'll just pull the .308 insert and use it as a .62 blunderbuss I've got a set of measuring cups around here somewhere, I can just scoop a half-cup or so of oversize bullets and tire-weight scraps and I'm to go! Actually, I might have to try that...

Ya blunder buss I like that ! You could drive a bull pin ( iron worker tool) down the end of that barrel and get a good taper going on . You won't need a funnel then , but I'm not sure how that stainless would react without a blue flame wrench ! But seriously I have made some pretty nice sinker molds out of aluminum ( easy to work) and go that route or by a bullet mold smaller than needed and canniblize to size once you find out what that rig likes ! Just think of harvesting a meal with a bullet you made and a gun Gary made ! Like Gary said earlier fly fishing is fun but even FUNNER with a fly you tied with materials you harvest from woods ! The fish even tastes better.

Fortunately, you don't actually have to mine for the lead!

You don't!!!!????

Ah nutz!!!

Gary,

Getting back to the OP; do you think barrel liners or other commercial barrel choices are consistent enough that they would reliably fit? I would think that liners must have a very consistent OD but do they really? What about the ID? Maybe every liner needs the same trial and error approach. Certainly the sizing advice should be heeded regardless of barrel source. Of course, even that will be seen as too much for some.

Hi Jerry,

As a part of reasons given for not shooting, I hear that the availability of proper ammo stops folks dead - who would otherwise shoot all of the time.

And so, based upon the premise that someone, somewhere must be shooting .., I figured it must be common knowledge to all but me - as to which readily available combos of barrels and slugs are available, consistent, and very accurate. Figured might be able to make it even easier for people to enjoy their chosen sport. Maybe they'll buy my super duper custom made barrel with gee wiz honest to goodness actual field tested and published world class results from the handmade amazingly precise Barned molds and sizing dies ............ and then buy a extra weekday barrel to shoot Walmart slugs, 1/2 MOA, when nobody else is looking!


Common now ..., no holding out on me. The barrels are on Ebay - right?

Gary

E-bay hates guns, probably not.