Velocity And Barrel Length


Technoid,

Here’s a question I haven’t seen in the two years I’ve been visiting your site.

How do the shotshell manufacturers and reloading component makers measure velocity? And, does barrel length significantly effect the velocity of a specific load? If so, is there a standard that we can use to calculate velocity loss/gain by the barrel inch?

Thanks, Dan

Dear Dan,

SAAMI (Sporting Arms and Ammunition Manufacturers Institute), a manufacturers trade group, set the standards for measuring American ammunition. 12 gauge shotshells are measured from a 30″ barrel (I’m not sure about sub-gauge) for velocity at 3 feet.

The chronographs the manufacturers use are more sophisticated than the “hobby” chronos that people like me use. My chrono only measures the lead pellet. The serious ones in the labs measure the three feet from the average center of mass of the shot cloud. This makes for a very slight difference in shell speed, but not very much.

Be aware that other countries measure their velocities in different ways. For example, the high velocities claimed for some English and Cypriot shells reflect their method of measurement and will be slower when measured by the US standards. Off hand I can’t think of any country with a more conservative measuring system than ours.

The effect of barrel length on shot velocity depends on the type of load you are using. Most target powders behind relatively light target loads burn quite quickly and develop full velocity within the first 20″ or less of the barrel. Very heavy field loads and most steel powders burn for a longer time and may be more affected by barrel length. A good average velocity loss is 15 fps for every 1″ under 30″, but loads will vary. As do we all.

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error, never in doubt.)

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Oils For Gas Guns


Dear Bruce,

What is your experience with “dry moly” spray lubes for guns like the 390 Beretta? Obviously the dry part is appealing, no oil or grease to catch stuff – but is the dry lube good enough to make the gun function reliably and not cause pre mature wear?

Dick

Dear Dick,

I really ought to do more of a piece on this. A lot of people have questions on gas gun lubrication. It’s really sort of like chili recipes- everyone has their favorite way of doing things. There is more than one way to do it that will satisfy.

The best advice that I can give you is that if your gas gun works to your satisfaction, keep doing what you are doing. If it doesn’t work the way you want it to, then I do have some suggestions. My way of keeping a gas gun running is definitely not the only way. There may be, and probably are, better ways, but what I do works for me and those who have tried it.

I use BreakFree CLP on the inside and outside of the piston, on the piston guide rod and inside the bolt (via the hold where the cocking lever goes). When my gun gets so dirty that it slows down and I am too lazy to clean it, I just add more BreakFree CLP. I usually put four or five drops on the inside of the piston, another four or five on the outside, a couple on the piston rod and two in the bolt. The bolt doesn’t need quite as much as that part doesn’t dry out as quickly. The oil put in the bolt sort of sloshes and sprays around and lubes the trigger, action rod, bolt and other moving parts.

I certainly haven’t tried every lube, grease, spritz, etc. out there, but I have tried BreakFree CLP, G-96 Gun Conditioner, G-96 Synthetic, WD-40, Ballistol, Shooter’s Choice, Hoppe’s, silicone, Lubriplate, bearing grease, Sportscare Ultra Lube, Kellube M12, Remington Dry Lube, graphite, Militec-1, White Lightning,Triflow, Fastex, TAL 5, FP 10, motor oil, Krieghoff GP Gun Pro, Sentry Smooth Kote and nothing at all.

Now that’s not everything on the market by a long shot and may not cover some miracle substance out there, but it does cover a pretty wide range. The Sentry Smooth Kote, White Lightning, Remington Dry Lube and graphite powders are dry lubes. The others are wet or wetish. At the moment I am testing the White Lightning and will test Pachmayr’s PRP rust preventative (only on the inside of the piston- it’s too gummy for other use).

I still haven’t found anything better than BreakFree CLP for keeping my gas operated Beretta 303 and 390s running. Here’s why: The problem with gas guns is an accumulation of burnt-on carbon. There really isn’t any lubrication problem to speak of. It’s carbon buildup. In spite of what is claimed for many of the oils, none that I have found, including the dry lubes, will keep carbon from building up on the Beretta’s gas piston. Nothing. Some oils claim that they “plate” the metal so that build up can’t adhere, but I have not seen any success with those products in my situation. Perhaps they work great in others, but not mine.

The ONLY thing that has worked for me, and that only half well, is BreakFree CLP because it contains a SOLVENT mixed in with the lubricant and preservatives. These lubricants and preservatives seem to keep the solvent from evaporating as quickly as it normally would when applied straight, as with Hoppes #9 and Shooters Choice- both excellent pure solvents. The other oils mixed in with BreakFree CLP’s solvent keep it wet for quite a while, well over 100 shots if you start pretty wet. When the solvent is kept moist, it breaks down the carbon into a liquid sludge and keeps it from adhering to th metal parts. Eventually, it dries out and the carbon hardens, but that takes some time. Squirting a bit more BreakFree CLP on the piston of a gummed up gun will always free it up enough to get you through the next bunch of shots. I certainly don’t think that BreakFree CLP is the end all and be all for gas guns, but until I find something that can dissolve carbon and stay liquid as long, I’ll use it.

As to premature wear on gas guns due to improper lubrication, I haven’t ever noticed it even during my most barbaric and insensitive testing. Remington always recommended that their 1100s be shot “dry”, but when I spoke to the reps the said that dry was recommended, not because it was necessarily best, but because most shooters would just sluice their 1100s down with WD-40. That WD-40 would stop the gas gun quicker that anything, so it was felt that dry with constant cleaning was the safest advice to give the general public. I always shot my 1100s slopping wet with BreakFree CLP and found that my guns could go longer without cleaning than when shot dry. If you clean your gun thoroughly ever 100 rounds, you can do pretty much anything that you want.

It is quite possible that the recommendation to shoot the guns dry was also due to the fact that the gas guns may be designed to have a certain amount of friction. Recoil operated guns are a different story entirely. I never found that lubrication and the increased bolt speeds that it produced caused any real problem in my guns if I kept a fresh mainspring installed (every 10,000 rounds). If I failed to keep a fresh spring, the 1100s beat themselves to death, usually separating at the magazine tube/ receiver juncture or cracking the receiver. The Beretta gas guns are very much stronger and longer lived than the 1100s were. I have a 303 with almost 60K on it now and it shows no sign of being near the end of its road. None of my six 1100s lasted over 40K, though I have heard of other people having better luck.

This is probably more than you EVER wanted to know about one guys opinions on lubing gas guns, but hey, I get paid by the word.

Boots off. Beer open.

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error, never in doubt.)

Posted in Shotgun related, Shotguns | 1 Comment

Barrel Length


Dear Bruce:

Years ago, standard skeet guns were 26″ long, with some people using 28″ barrels. Now, 28″ seems to be “standard” with many shooters even moving to 30″ barrels.

Like skeet (at least as it was originally conceived), sporting clays and FITASC emulates field shooting. But as I look at the big names in those sports, very un-field-like 32″ barrels tend to predominate (although 30″ still seems to be most popular with the average shooter).

As in most matters of choice, I’m sure personal taste, physiognomy, and typical course layouts will dictate an individual’s barrel length. But do you consider longer barrels to be the starting point for a serious sporting gun, or are they best left to the experts? Is 32″ already standard for the UK, and is the US yet to catch up? Do any of the top shots still use 30″ or shorter barrels?

Charles

Dear Charles,

By “sporting gun” I am going to assume that you mean “sporting clays”. Sporting clays may have started out as emulating the field sports, as did skeet, but like skeet it has become an end in itself and, for better or worse, proper field guns have little place in advanced sporting. My advice to sporting clays shooters, indeed to all shooters in whatever sport, is to shoot the longest barrel that you are comfortable with. “Comfortable”, ay, there’s the rub. That depends both on the shooters physical makeup and shooting style, as well as the game being shot.

If we consider the Brits to be the paragon in sporting, we could follow them as they have gone from 30″ to 32″ (for many, but by no means all) and now rumor has it back to 30″. I have always recommended 30″ as the starting point for a sporting clays gun, though I have shot some 32″ guns that felt very nice. Andy Duffy’s 32″ Browning B25 is nicely balanced, but the 32″ Perazzi of Stuart Clarke that I tried was far too barrel LIGHT (as opposed to our nose-heavy trap-oriented Perazzis sold in the US). Remember, it is a combination of length and weight, not just length.
Many of the mass produced, but in no way mechanically inferior, guns from Browning Japan and Beretta, carry a lot of barrel weight due to those screw chokes. Browning in particular, due to those massive Invector Plus chokes. A 32″ Japanese Browning can be a real handful with a very, very different feel than one of Andrew Litt’s 32″ Belgian or MIroku solid choke sporters. It isn’t just length.

Over here, many of the advanced sporting clays shooters seem to have embraced the Beretta 390 gas gun. With very few exceptions, the 30″ version is selected, often with some sort of aftermarket extended choke adding another 1″. Due to the extra 3-1/2″ of the automatic’s receiver, these guns are the equivalent of a 34-1/2″ O/U! Yet, the American’s scores are slowly catching up to the English and a visiting Brit is no longer assured of winning everything he enters (except George Digweed who wins everything on both sides of the Atlantic).

What does length, in and of itself, do for you? Basically it permits more precise pointing, especially on long targets. This is why handicap trap shooters have long preferred long single barrel guns. Handicap trap is a pointing/aiming sport and long, thin barrels mean precision.

In sporting, due to the wide variety of shots, a gun has to be more general purpose. Still, the general opinion at the top is that long barrels give a bit more of an edge on the long targets and don’t really hurt much on the short stuff. The good guys feel that they will hit the short stuff with anything and want something precise for those long bird shoot-offs. The advanced shooters also know where to start their barrels, so they can keep movement down to a minimum if they want to. This makes it easier to handle extra barrel length.

Ballistically, with modern fast burning target loads, there is very little velocity difference between barrel lengths. The figure of 15 fps per 1″ of length is often used, but I wonder if it is even that much sometimes.

Bottom line: use what you are comfortable with and balances well in the particular gun you are choosing. 30″ is the “standard”, but if a certain 28″ or 32″ gun feels better to you, go that way.

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error, never in doubt.)

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Ginny Thrasher and Matt Emmons Earn USA Shooting’s Top Honors for 2016 Performances | USA Shooting


Source: Ginny Thrasher and Matt Emmons Earn USA Shooting’s Top Honors for 2016 Performances | USA Shooting

Posted in Shotguns | 1 Comment

Lowering 390 Stock


dear bruce ,

i purchased a beretta 390 sport, i have used the shims which came with my gun in every combination but still cannot lower the stock enough ,the end of the barrel is higher than the front of the barrel any ideas. also would an english stock get me any lower if so does beretta make any that fit the 390.. thanks for taking the time to respond.

john

Dear john,

I haven’t seen any Beretta autos with English stocks. Besides, the English stock really only affects the pistol grip area, not the comb at top where stock height is determined.

A surprisingly large number of people have found the Beretta sporter’s stock to be uncomfortable or ill-fitting. For some reason Italian design stocks are less universal in their fit than Remington, Winchester, Browning stocks are. Perhaps it is in the pistol grip, but it may also be attributable to the “heads up” set up of many Italian guns.

I can think of two choices you might try:

1) contact Rich Cole at Cole Gunsmithing, Rt. 123, Harpswell, ME 04079, Tel: 207-833-5027, , and ask if there is another set of shims that will lower the stock more than the standard set that comes with the gun. I believe that there is.

This may do what you want. It may not. Personally, I found that the Beretta Sporter stock on my gun had excessive drop from nose to heel (the comb slanted down too much) no matter what I did to it. Even though I could get the height right for my shooting, the extreme downward slope of the comb increased face slap for me to an unacceptable degree. I crawl my stocks a bit and am far more comfortable with a close to parallel comb. If you have a shorter neck and shoot with your head more erect, this may not be as much of a problem.

2) The other easy alternative is simply to shave some wood off the top of the comb. It isn’t brain surgery, but just go slow. Cut a little, test a lot. You will have to refinish the top of the stock (it never comes out matching quite right when I do it), but at least you will have a gun that you can shoot. Unlike Beretta trap stocks for the 390, the sporter stocks and field stocks are relatively easy to obtain- perhaps because so many people take them off in the first place.

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error, never in doubt.)

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Choke Opinion


cheap choke?????/ a choke isa contriction .mossberg or briley they do the same thing. the idea that a briley will make you shoot better is BUNK

[unsigned]

Dear unsigned,

Did I say that a Briley choke would make you shoot better just because it was a Briley choke? If so, I must have been having a senior moment. In my tests, I haven’t found Briley chokes to outperform any other mass-produced brand when constrictions are identical, but they aren’t any worse either. And they do have some advantages.

First, they offer both flush and extended chokes so that you can pick what you like. I also like the idea that you can order a particular constriction directly from Briley and actually have a chance of getting it for less than a king’s ransom. That’s nice. In my experience, Briley service has been excellent too. One difference in chokes that you can measure is concentricity. Mass produced chokes can easily be “out of round” and that will effect your pattern slightly. Briley’s aren’t bad in this area.

As far as the finish on the inside of the choke goes, I have seen Briley’s rough and I have seen them smooth. My guess is that it is just a production variance, but there are choke makers who actually espouse one or the other. Rough choke advocates feel that the choke can be used to retard the wad and keep it out of the shotstring. Lujtic roughens his chokes for this reason. Others feel that a smooth choke is better so that it doesn’t build up residue. Personally, I don’t notice much difference in performance. Maybe it might affect shotstring, but I can’t really measure that.

I would be very interested in having you send me the spread sheets on your choke experiments so that I can match them up to mine. I am always looking to add to my data and I am sure that your personal tests will prove enlightening.

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error, never in doubt.)

Posted in Shotgun related | 2 Comments

Rust Prevention


I’ve always avoided using WD-40 on my guns due to its reputation for gumming actions. I never thought of it as a rust preventative. However the rust preventatives I’ve had faith in may not be as good as I thought. My gun storage situation (dry room, Goldenrod in safe) doesn’t present too much of a rust problem so I might not be as critical as I should be.

Take a look at this from Brownell’s:

http://www.brownells.com/aspx/NS/GunTech/NewsletterArchive.aspx?p=0&t=1&i=503

You learn something new every day.

Bottom line: if what you are presently doing to prevent rust is working for you, don’t change a thing. If it isn’t, checkout that Brownell’s video.

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error. Never in doubt.)
http://www.ShotgunReport.com

Posted in Shotguns | 3 Comments