Shot Talk
In my column "No Worries" (July/August) I covered some technical subjects that many shooters worry about but needn't be worried about once they examine the facts. This time I'm going to look at shotgunning issues that shooters rightfully worry about, especially once they know the facts.
Long Shells in Short Chambers
As discussed in "No Worries," it is always OK to fire shotshells that are the same length or shorter than the length for which a given barrel has been chambered. That's why many barrels and owner's manuals contain language stating, for example, "For 3" or shorter 'X'-gauge ammunition." Notice there is no caveat on how much shorter.
Problems start when a shooter elects to fire a shotshell longer than that for which a barrel is chambered-say, a 23/4" shell in a barrel chambered for 21/2" shells. The issue is not that the 23/4" shell won't fit into the 21/2" chamber. It will fit fine, allowing the gun to be closed without incident. The issue is that, upon firing, the crimp area of a 21/2" fold-crimp shotshell always unfolds fully within its 21/2" chamber, and if a 23/4" fold-crimp shell were to unfold in the same chamber, the crimp mouth would extend 1/4" into the forcing cone immediately beyond the chamber. Because the forcing cone is narrower in diameter than the chamber, the ejecta now would have to squeeze through the narrower inner diameter created by the thickness of the crimp walls lining the forcing cone. This would create increased friction and raise pressure.
How much? From my testing, you can count on at least a 1,500-psi increase in 12 gauge for the first 1/4" of excess shell length. And the pressure increases exponentially with each additional 1/4". This is especially true the smaller the gauge; you can easily cause a 4,000- to 5,000-psi pressure increase from firing 3" .410 bore ammo in 21/2" .410 chambers.
Now will this pressure increase cause the gun to blow up? That depends on the gun, but usually not. What it does cause is excessive strain on the bore and chamber area of the barrel that is cumulative over time. This can result in cracking of the chamber or bore just forward of the chamber. In the short term it also can cause cracking in wood components, and-especially with autoloaders-it will result in little action parts cracking and even breaking prematurely. Last, it always will result in increased recoil.
Increased Recoil
You're getting older, and hopefully you're getting smarter. You're starting to realize that in shotgunning, recoil is always a negative. And the higher the recoil you have to deal with, the more inhibited your shooting success tends to be. You've proven this to yourself by shooting lighter and/or slower loads, and it quickly has become clear that not only have they been more pleasant to shoot but also your scores have improved.
Now you're getting it.
Recoil should be a serious worry in the minds of any shotgunner wanting to shoot well and especially those who want to shoot better. Once it is appreciated that lighter gun weights increase recoil and that heavier and/or faster loads increase recoil, any change in your shotgunning regime in the direction of these three variables is reason for concern.
For example: You've been shooting a certain shotgun type well but have decided to shoot the same shotgun type in a smaller gauge. On the surface that's a good move recoil-wise, because smaller-gauge ammunition generally is loaded with lighter shot charges. But if the particular smaller-gauge gun you're moving to is significantly lighter and for some reason the shot-charge weight and velocity level of the smaller-gauge load is the same or similar to the larger-gauge loads you've been shooting, a big red worry flag should start waving. You're simply going to have to deal with increased recoil from the lighter gun.
You can overcome this worry by being certain when shooting the lighter, smaller-gauge gun that you use proportionally lighter-weight loads at the same or preferably slower velocities than those of your larger-gauge loads. Without working through the recoil equation (which I'll do in a future issue), if you switch from, say, a 71/2-pound 12-gauge shooting 11/8-oz lead loads at 1,250 fps to a 61/2 pound 20-gauge, you're going to be dealing with increased recoil levels unless you make sure you're using no heavier than 7/8-oz 20-gauge loads at 1,200 fps. If you don't observe these details, pretty soon the increased recoil of switching to the lighter 20-gauge will start to erode your shooting success. Yes, the lighter gun may well allow you to swing faster and carry it farther afield, but the heavier recoil levels transferred by the poorly chosen 20-gauge loads will slowly start to beat back your shooting success.
Pretty soon you'll be talking to yourself, saying things like, I just can't seem to shoot this 20-gauge as well as my old 12. Must be the lower effectiveness of the smaller gauge. Actually, gauge didn't have anything to do with it; recoil did.
High Working Pressures
Here's a bigger worry for a lot of readers. Many American shotgunners buy foreign-made shotguns. Some are imported and marketed by major outfits or US-based subsidiaries of the foreign manufacturers. Other foreign-made guns are merely imported by shotgunners who rename the firearms with their own private labels and then advertise and sell them.
The worry here is pressure levels if you intend to shoot American-made ammunition through these guns. The fact is that proof testing of shotguns in the UK and Europe, for example, is done differently in terms of both procedure and proof-load levels than is proof testing of American-made shotguns. And I have not yet found a ballistician or proofing firm anywhere who can give me an accurate conversion rule from European CIP proofing methodologies and proof levels to US voluntary SAAMI standard proofing methodologies and proof levels.
So unless your importer or American subsidiary company can assure you that the shotgun you're buying is perfectly capable of regularly withstanding American shotshell service-load pressures, you are conducting an experiment whenever you fire domestic shells through that gun.
Many US shooters are playing self-styled proof-house experts by deciding-without running extensive destructive tests-that their foreign-made guns can withstand "X" level of chamber pressure. That pressure level is usually a few thousand pounds below what the SAAMI voluntary standard is for the maximum average pressure (MAP) of service loads in that gauge. Then they either search for low-pressure factory loads or reload shells themselves. They have found that some US shotshell manufacturers, including Polywad, RST and now Federal, are offering lines of reduced-pressure shells in both standard and shorter lengths for different gauges.
I am reasonably confident but do not know for certain that a 12-gauge shell of the proper length or shorter that develops only 5,000 psi and contains lead shot can be fired safely in most European-made 12-gauge, non-Damascus-barreled guns. But what if the pressure is 6,000 or 7,000 psi? Where's the cutoff? No one knows for any firearm unless and until proof testing and preferably destructive testing have been conducted with that firearm. And until I am presented with the results of that testing or assurances from a gun's foreign manufacturer or US representative, I can never condone the use of such ammunition in any such firearm.
So a word to the wise: Before you fire any American-made ammunition in your foreign-made shotgun, be certain that you check with the gun's manufacturer and/or US importer regarding what kind of shotshells-load weights, shot types and velocity levels-are safe for use in that fire-arm. If they can't give you a clear and straight answer, you and you alone are taking the risk. And if your gun's manufacturer is long out of business, you'll probably never be able to acquire a definitive answer. In that case I must caution: caveat emptor.
To correspond with Tom Roster or to order his third-edition reloading manual on buffered lead and bismuth shotshells, his new HEVI-Shot reloading manual, his 75-page manual on shotgun-barrel modifications or his instructional shooting videos, contact Tom Roster, 1190 Lynne-wood Blvd., Klamath Falls, OR 97601; 541-884-2974; tomroster@charter.net.
Long Shells in Short Chambers
As discussed in "No Worries," it is always OK to fire shotshells that are the same length or shorter than the length for which a given barrel has been chambered. That's why many barrels and owner's manuals contain language stating, for example, "For 3" or shorter 'X'-gauge ammunition." Notice there is no caveat on how much shorter.
Problems start when a shooter elects to fire a shotshell longer than that for which a barrel is chambered-say, a 23/4" shell in a barrel chambered for 21/2" shells. The issue is not that the 23/4" shell won't fit into the 21/2" chamber. It will fit fine, allowing the gun to be closed without incident. The issue is that, upon firing, the crimp area of a 21/2" fold-crimp shotshell always unfolds fully within its 21/2" chamber, and if a 23/4" fold-crimp shell were to unfold in the same chamber, the crimp mouth would extend 1/4" into the forcing cone immediately beyond the chamber. Because the forcing cone is narrower in diameter than the chamber, the ejecta now would have to squeeze through the narrower inner diameter created by the thickness of the crimp walls lining the forcing cone. This would create increased friction and raise pressure.
How much? From my testing, you can count on at least a 1,500-psi increase in 12 gauge for the first 1/4" of excess shell length. And the pressure increases exponentially with each additional 1/4". This is especially true the smaller the gauge; you can easily cause a 4,000- to 5,000-psi pressure increase from firing 3" .410 bore ammo in 21/2" .410 chambers.
Now will this pressure increase cause the gun to blow up? That depends on the gun, but usually not. What it does cause is excessive strain on the bore and chamber area of the barrel that is cumulative over time. This can result in cracking of the chamber or bore just forward of the chamber. In the short term it also can cause cracking in wood components, and-especially with autoloaders-it will result in little action parts cracking and even breaking prematurely. Last, it always will result in increased recoil.
Increased Recoil
You're getting older, and hopefully you're getting smarter. You're starting to realize that in shotgunning, recoil is always a negative. And the higher the recoil you have to deal with, the more inhibited your shooting success tends to be. You've proven this to yourself by shooting lighter and/or slower loads, and it quickly has become clear that not only have they been more pleasant to shoot but also your scores have improved.
Now you're getting it.
Recoil should be a serious worry in the minds of any shotgunner wanting to shoot well and especially those who want to shoot better. Once it is appreciated that lighter gun weights increase recoil and that heavier and/or faster loads increase recoil, any change in your shotgunning regime in the direction of these three variables is reason for concern.
For example: You've been shooting a certain shotgun type well but have decided to shoot the same shotgun type in a smaller gauge. On the surface that's a good move recoil-wise, because smaller-gauge ammunition generally is loaded with lighter shot charges. But if the particular smaller-gauge gun you're moving to is significantly lighter and for some reason the shot-charge weight and velocity level of the smaller-gauge load is the same or similar to the larger-gauge loads you've been shooting, a big red worry flag should start waving. You're simply going to have to deal with increased recoil from the lighter gun.
You can overcome this worry by being certain when shooting the lighter, smaller-gauge gun that you use proportionally lighter-weight loads at the same or preferably slower velocities than those of your larger-gauge loads. Without working through the recoil equation (which I'll do in a future issue), if you switch from, say, a 71/2-pound 12-gauge shooting 11/8-oz lead loads at 1,250 fps to a 61/2 pound 20-gauge, you're going to be dealing with increased recoil levels unless you make sure you're using no heavier than 7/8-oz 20-gauge loads at 1,200 fps. If you don't observe these details, pretty soon the increased recoil of switching to the lighter 20-gauge will start to erode your shooting success. Yes, the lighter gun may well allow you to swing faster and carry it farther afield, but the heavier recoil levels transferred by the poorly chosen 20-gauge loads will slowly start to beat back your shooting success.
Pretty soon you'll be talking to yourself, saying things like, I just can't seem to shoot this 20-gauge as well as my old 12. Must be the lower effectiveness of the smaller gauge. Actually, gauge didn't have anything to do with it; recoil did.
High Working Pressures
Here's a bigger worry for a lot of readers. Many American shotgunners buy foreign-made shotguns. Some are imported and marketed by major outfits or US-based subsidiaries of the foreign manufacturers. Other foreign-made guns are merely imported by shotgunners who rename the firearms with their own private labels and then advertise and sell them.
The worry here is pressure levels if you intend to shoot American-made ammunition through these guns. The fact is that proof testing of shotguns in the UK and Europe, for example, is done differently in terms of both procedure and proof-load levels than is proof testing of American-made shotguns. And I have not yet found a ballistician or proofing firm anywhere who can give me an accurate conversion rule from European CIP proofing methodologies and proof levels to US voluntary SAAMI standard proofing methodologies and proof levels.
So unless your importer or American subsidiary company can assure you that the shotgun you're buying is perfectly capable of regularly withstanding American shotshell service-load pressures, you are conducting an experiment whenever you fire domestic shells through that gun.
Many US shooters are playing self-styled proof-house experts by deciding-without running extensive destructive tests-that their foreign-made guns can withstand "X" level of chamber pressure. That pressure level is usually a few thousand pounds below what the SAAMI voluntary standard is for the maximum average pressure (MAP) of service loads in that gauge. Then they either search for low-pressure factory loads or reload shells themselves. They have found that some US shotshell manufacturers, including Polywad, RST and now Federal, are offering lines of reduced-pressure shells in both standard and shorter lengths for different gauges.
I am reasonably confident but do not know for certain that a 12-gauge shell of the proper length or shorter that develops only 5,000 psi and contains lead shot can be fired safely in most European-made 12-gauge, non-Damascus-barreled guns. But what if the pressure is 6,000 or 7,000 psi? Where's the cutoff? No one knows for any firearm unless and until proof testing and preferably destructive testing have been conducted with that firearm. And until I am presented with the results of that testing or assurances from a gun's foreign manufacturer or US representative, I can never condone the use of such ammunition in any such firearm.
So a word to the wise: Before you fire any American-made ammunition in your foreign-made shotgun, be certain that you check with the gun's manufacturer and/or US importer regarding what kind of shotshells-load weights, shot types and velocity levels-are safe for use in that fire-arm. If they can't give you a clear and straight answer, you and you alone are taking the risk. And if your gun's manufacturer is long out of business, you'll probably never be able to acquire a definitive answer. In that case I must caution: caveat emptor.
To correspond with Tom Roster or to order his third-edition reloading manual on buffered lead and bismuth shotshells, his new HEVI-Shot reloading manual, his 75-page manual on shotgun-barrel modifications or his instructional shooting videos, contact Tom Roster, 1190 Lynne-wood Blvd., Klamath Falls, OR 97601; 541-884-2974; tomroster@charter.net.
- By: Tom Roster
