Shotgun chamber adapter vs rifle chamber adapter

TruthTellers · January 1, 2017, 02:17 PM

For those unfamiliar with these, a shotgun adapter is an tube of steel that fits into the chamber of a shotgun and come in lengths as short as 3 inches long up to 18 inches long. The tube is chambered for a variety of smaller cartridges and is rifled to increase accuracy.

The rifle chamber adapters are similar, but not exactly the same. These adapters look the same as empty rifle cartridge brass, but instead of a primer pocket, there is a chamber machined to accept pistol cartridges of the same or similar bore diameter of the rifle as this adapter does not have a barrel of it's own; it uses the rifle's barrel to impart spin on the bullet.

I'd like to know if the shotgun adapter is more accurate than the rifle chamber adapter. I'm thinking that it probably is as it has it's own barrel made specifically for the pistol bullet being shot, where the rifle adapter is using a barrel that was made for shooting a rifle bullet.

I'm I correct in this assumption?

What kind of accuracy can I expect at 25, 50, and 100 yards with both the rifle adapter and shotgun adapter?

Snyper · January 1, 2017, 07:57 PM

They are all pretty much gimmicks and are not noted for their accuracy.
In theory they sound good, but in practice they leave a lot to be desired.

dogtown tom · January 1, 2017, 09:58 PM

Quote:

Snyper They are all pretty much gimmicks and are not noted for their accuracy.
In theory they sound good, but in practice they leave a lot to be desired.

This.

FITASC · January 1, 2017, 10:20 PM

Yep..................accuracy will be about as good as pistol shot capsules at 25 yards

TruthTellers · January 2, 2017, 12:25 AM

Quote:

Originally Posted by Snyper

They are all pretty much gimmicks and are not noted for their accuracy.
In theory they sound good, but in practice they leave a lot to be desired.

So, you've used them before? Are you sure it wasn't the ammo?

**44 AMP** · January 3, 2017, 01:30 PM

Quote:

What kind of accuracy can I expect at 25, 50, and 100 yards with both the rifle adapter and shotgun adapter?

I don't think anyone can give you an honest answer other than "you'll have to see what you get in your gun(s)".

First off, you are talking about two different kinds of accuracy. One is the mechanical accuracy of the adapters themselves, the other is the level of accuracy that they will deliver, for you, in your gun(s). These are related, but quite DIFFERENT things.

Accuracy in your gun is dependent on many factors, not just the accuracy of the insert itself, OR the fit of the ammo in your barrel. Also included is the fit (positioning) of the adapter in your chamber (which will be different for each shot), and how consistent that positioning is, relative to whatever you are using for sights.

For example, I would expect the shotgun adapter, with its own integral barrel to be mechanically more accurate than the rifle adapter, BUT how much, if any, of that advantage (if it actually exists) can you USE with the bead sight of a shotgun???

Also, forget 100yards. The entire design purpose of the sub caliber adapters is to take small game/pests at SHORT range, without needing to use the full size cartridge.

With all the different factors that can be involved, (including stacking tolerances) the only way to know what performance you will get from your guns and adapters (and the ammo you use) is to shoot them in your guns and see.

If your specific combination of things gets you minute of squirrel at 25yds, I'd consider that pretty good. Minute of rabbit at the same distance would be acceptable to me, but not really good. If you're looking for minute of angle accuracy (at any distance), I'd be amazed if you got it. (and, if you do, you have a pearl of great price!)

No, I haven't personally used these adapters, so my opinion is just theory, and worth what you paid for it.

Good Luck, and let us know what your field tests give you.

TruthTellers · January 4, 2017, 02:16 AM

As I stated in the OP, I feel that the shotgun adapter is more likely to be the most accurate because the barrel and chamber are made for a specific cartridge. The good news is my shotgun is an Over/Under and has a fixed rear sight and a fiber optic front, so that set up is much better than a simple bead, which I think is the issue people have accuracy wise with these adapters.

I think I'm leaning towards the shotgun adapter. I can get it with a 10 inch length, which is perfect for .32 H&R Magnum or S&W Long, plus it'll be a short, thick barrel and give it plenty of rigidity and cut down on vibrations.

I agree with you that it looks like this is something I'm just going to have to test out for myself because there are a lot of variables here based on others personal opinions and experiences. Guess it's time I make my own experience

dogtown tom · January 4, 2017, 10:36 AM

What is your intended use?

I ask because these chamber adapters have been out for decades and have a poor reputation for anything but "Hey, looky.....I can shoot a .32acp through my 30-06".

TruthTellers · January 4, 2017, 12:05 PM

^ Testing to see what handloads give the best groups and once that's found using as a small game rifle that's not .22 LR.

TruthTellers · January 9, 2017, 01:51 PM

I want to update this thread for those who've been following it.

I've been in email contact with Ace of MCA Sports, he makes shotgun adapters in 3 inch, 10 inch, and 18 inch lengths in a large variety of cartridge chambers as well as rifle adapters.

There's a lot of information that's not on his website, such as whether the inserts are stainless steel or blued, if they're rifled (I assume for $100 they are rifled), for the rimmed cartridges if there is a recess or groove to dig a fingernail in and pull the spent case out, etc.

I will post the answers I get when I get them. I do intend to buy one of these in .32 H&R Magnum as MCA Sports is the only company that makes a .32 caliber adapter. Once I get it in 8-12 weeks, I'll do a review on it with my shotgun and post pics of the targets and get more information on what's what with the potential accuracy on these adapters.

For that review I have decided I will not use handloads and instead use factory S&W Long and H&R Magnum ammo because that's available to everyone.

ShootistPRS · January 9, 2017, 03:29 PM

I have never seen rifle/pistol adapters for a shotgun but I can see the potential there. I have made chamber adapters for 12 ga. shotguns in 20 and 410 bore. The velocity is close to the same as if fired from a standard bore gun and patterns from a full choke 12 ga, with 410 cases does not differ much from a standard 410. My brother lives in a cabin that we built out in the country and he uses the 410 in his 12 ga. for rabbits and grouse. He does as well with the 410 as with the 12ga. It is cheaper to reload the 410 than it is to buy 12ga. or 410 shells.

With a rifled insert accuracy would depend on the fit and repeatable indexing of the barrel. One might use o-rings to provide the proper fit and an extractor groove for proper indexing. while it might never be a target rifle it could be used for small and medium game or camp meat at close range.
I'm sure it could be made more accurate with the application of a tapered retaining nut at the muzzle and an accurate fit at the breech. That kind of insert would have to be cut to the individual gun and not a mass produced piece like is being discussed here.

FITASC · January 9, 2017, 04:11 PM

Quote:

For that review I have decided I will not use handloads and instead use factory S&W Long and H&R Magnum ammo because that's available to everyone.

For the price of that ammo, just using a low volume reload in your O/U would most likely work for your stated purpose - "small game hunting with something other than a .22"

TruthTellers · January 10, 2017, 03:14 AM

Quote:

For the price of that ammo, just using a low volume reload in your O/U would most likely work for your stated purpose - "small game hunting with something other than a .22"

I'm doing that for the review, not for future personal use. Leaving the review out of this, I'd be shooting handloads only.

As for low volume of shot, that's not the point because this test isn't just to test a shotgun adapter, it's to test the .32 as well. I have a special round ball load in mind for the .32 and want to see how it preforms from the adapter. If it's decent out to a certain range, it gives me hope that the same load will work in the upcoming Henry .327 Big Boy, but better because it's a real rifle.

If said load doesn't work out too well, at least I know and if the adapter doesn't work too well either, then I won't get another and at least this will be documented on video for future TruthSeekers to discover what TruthTellers found out.

I'm practically going on the lowercase T for you guys to get a definitive answer and you're all saying Barabbas over there seems like a selfless guy and oh look! He's got a Colt Python too!

Either way, a little over $100 for what amounts to a .32 S&W/H&R rifle is a lot less than what the Marlin .32 H&R rifles are selling for or the Henry for that matter.

dogtown tom · January 10, 2017, 11:09 AM

The gun buying public has already done the review for you.

Chamber inserts/adapters give less than stellar performance in any firearm.

If they worked well, their reputation would be far and wide not to mention manufacturers would offer them as well. (They don't) Experienced shooters know they are a near useless gimmick. You've heard from several people on this forum that have told you they are a waste of $$$. But it's your money.

Frankly, I have no earthly idea why anyone would be interested in a review of a "round ball" .32acp load.........those reviews were done before the Civil War, hence the Minie Ball. Other than the .22BB rimfire cartridge no one loads a round ball for good reason. They are less accurate and inferior to conical bullets in every way.

roashooter · January 10, 2017, 12:18 PM

Quote:

The gun buying public has already done the review for you.
Chamber inserts/adapters give less than stellar performance in any firearm.

If they worked well, their reputation would be far and wide not to mention manufacturers would offer them as well. (They don't) Experienced shooters know they are a near useless gimmick. You've heard from several people on this forum that have told you they are a waste of $$$. But it's your money.

Frankly, I have no earthly idea why anyone would be interested in a review of a "round ball" .32acp load.........those reviews were done before the Civil War, hence the Minie Ball. Other than the .22BB rimfire cartridge no one loads a round ball for good reason. They are less accurate and inferior to conical bullets in every way.

Well said!!

TruthTellers · January 10, 2017, 12:59 PM

Quote:

The gun buying public has already done the review for you.
Chamber inserts/adapters give less than stellar performance in any firearm.

All using the bead front sight which is far inferior means to shoot a bullet than a shotgun w/ front and rear sights or a scope.

johnwilliamson062 · January 10, 2017, 01:01 PM

Quote:

With a rifled insert accuracy would depend on the fit and repeatable indexing of the barrel.

That is the key. The bores are almost certainly not perfectly concentric, so everytime an insert is installed the adapter muzzle changes orientation slightly. I remember reading about someone modifying a single shot shotgun by cutting or soldering a tab in which the adapter would index and having reasonably good results. Some have marked it and manually lined them up with ok results. Everything I have read from people who just slid the insert in is no repeat-ability whatsoever.
And it is a given the sights will be off significantly from adapter to adapter and against the original cartridge/shell.

I was intent to buy one from MC Ace some years ago,maybe ten, and just had awful communication problems with them. I think it was a short term issue within the company. If it turns out well for you I may try again.

TruthTellers · January 10, 2017, 02:01 PM

^He's been replying to every email I've sent him. From posts on forums I've read made about MCA years ago, there were communication issues when people tried to contact him. From what I gather Ace works in construction, so Winter time is likely the best time to contact him, Summer time is worst.

About indexing in the barrel, I plan to find which orientation the adapter works best in and scribing a line at 12 O'Clock. Ace mentioned this when I asked if he cuts a recess in the adapter to help remove the spent casing, he says he can do it, but believes it's best for one to test which position the adapter shoots best in and filing a groove or recess at 12 O'Clock and using that as the index position.

kozak6 · January 11, 2017, 04:28 AM

Have you asked him what kind of accuracy to expect?

johnwilliamson062 · January 11, 2017, 07:39 PM

My understanding is the product itself is quite accurate. At least in examples where people have epoxied the tubes into hosts, which obviously defeats the purpose somewhat. Yes, I read a forum or blog post by someone at some point who did just that. The problem is entirely in the dimensions of the host gun chamber and barrel, which varies, combined with the orientation.

I've not read a knowledgeable poster claiming the MCA product was out of spec, poorly finished or anything similar.

One thing that has always baffled me is how these inserts can allow X39 to be safely fired through a 12ga shotgun. Almost 40,000 PSI difference between the two rounds.

TruthTellers · January 12, 2017, 02:18 AM

You forget that the adapter itself is a pretty thick piece of steel at the chamber of a 12 gauge shotgun.

johnwilliamson062 · January 12, 2017, 08:49 PM

True, but I don't think the hinges on most single shots are designed for those pressures. I know there are limits on what barrels could be attached to the H&R shotguns. Would an insert change that?

TruthTellers · January 13, 2017, 02:37 AM

I don't have the answer to that. I will say that when I asked if a .327 Magnum insert could be made, Ace of MCA Sports said that it was too hot for a shotgun, however he said that the .32 H&R Magnum adapter was capable of shooting the hottest Buffalo Bore had to offer, which is considered a +P load.

TruthTellers · January 23, 2017, 02:24 PM

Update, I received the adapter today, 2 months ahead of what is quoted on the mcace website. Here's a picture of the item:

The OD turning has rough tool marks and a so-so finish that I can't tell is blued or black oxided, but the bore looks smooth as glass, which is what counts most. This is a 10 inch adapter and it has one O-ring close to the muzzle, other adapters I've seen that are a couple inches shorter have two O-rings closer to the chamber.

I'm not sure what effect this will have on accuracy.

Anyway, the insert fits very tight in the 12 gauge's bore. That one O-ring is doing it's job making sure the adapter won't rotate in the bore while the action is closed and it also is going to keep the gasses from going back into the 12 gauges chamber.

I'll make another update on the .32 H&R adapter's performance when I get some trigger time at the range. I have a head cold at the moment, so this won't be for a week or two.

natman · January 25, 2017, 01:12 PM

I played around with a 32 ACP adapter in a 30-30 single shot. There are a few issues with the rear loading adapter.

As noted, accuracy is so-so. Rifle accuracy buffs fret over differences of a few thousandths of an inch of bullet jump; the adapter supplies full inches of bullet jump. The long jump before the bullet engages the rifling also affects ballistics because the bullet has so much free travel that the pressure never gets a chance to build up properly. By the time the bullet finally does engage the rifling, the powder is mostly burned. This results in a dirty burn and I suspect that velocity suffers as well.

There are rifle adapters that put the pistol cartridge in front and have an internal firing pin. They are much more expensive and a lot slower to reload.

A shotgun adapter with a properly dimensioned chamber and barrel would probably be more mechanically accurate, but this would be offset by the primitive sights found on most shotguns.

January 1, 2017, 02:17 PM	#1
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	Shotgun chamber adapter vs rifle chamber adapter For those unfamiliar with these, a shotgun adapter is an tube of steel that fits into the chamber of a shotgun and come in lengths as short as 3 inches long up to 18 inches long. The tube is chambered for a variety of smaller cartridges and is rifled to increase accuracy. The rifle chamber adapters are similar, but not exactly the same. These adapters look the same as empty rifle cartridge brass, but instead of a primer pocket, there is a chamber machined to accept pistol cartridges of the same or similar bore diameter of the rifle as this adapter does not have a barrel of it's own; it uses the rifle's barrel to impart spin on the bullet. I'd like to know if the shotgun adapter is more accurate than the rifle chamber adapter. I'm thinking that it probably is as it has it's own barrel made specifically for the pistol bullet being shot, where the rifle adapter is using a barrel that was made for shooting a rifle bullet. I'm I correct in this assumption? What kind of accuracy can I expect at 25, 50, and 100 yards with both the rifle adapter and shotgun adapter?

January 1, 2017, 07:57 PM	#2
Snyper Senior Member Join Date: December 16, 2013 Location: Eastern NC Posts: 3,047	They are all pretty much gimmicks and are not noted for their accuracy. In theory they sound good, but in practice they leave a lot to be desired. __________________ One shot, one kill

January 1, 2017, 10:20 PM	#4
FITASC Senior Member Join Date: December 6, 2014 Posts: 6,440	Yep..................accuracy will be about as good as pistol shot capsules at 25 yards __________________ "I believe that people have a right to decide their own destinies; people own themselves. I also believe that, in a democracy, government exists because (and only so long as) individual citizens give it a 'temporary license to exist'—in exchange for a promise that it will behave itself. In a democracy, you own the government—it doesn't own you."- Frank Zappa

January 4, 2017, 10:36 AM	#8
dogtown tom Senior Member Join Date: January 23, 2006 Location: Plano, Texas Posts: 3,072	What is your intended use? I ask because these chamber adapters have been out for decades and have a poor reputation for anything but "Hey, looky.....I can shoot a .32acp through my 30-06". __________________ Need a FFL in Dallas/Plano/Allen/Frisco/McKinney ? Just EMAIL me. $20 transfers ($10 for CHL, active military,police,fire or schoolteachers) Plano, Texas...........the Gun Nut Capitol of Gun Culture, USA https://www.youtube.com/watch?v=pELwCqz2JfE

January 10, 2017, 11:09 AM	#14
dogtown tom Senior Member Join Date: January 23, 2006 Location: Plano, Texas Posts: 3,072	The gun buying public has already done the review for you. Chamber inserts/adapters give less than stellar performance in any firearm. If they worked well, their reputation would be far and wide not to mention manufacturers would offer them as well. (They don't) Experienced shooters know they are a near useless gimmick. You've heard from several people on this forum that have told you they are a waste of $$$. But it's your money. Frankly, I have no earthly idea why anyone would be interested in a review of a "round ball" .32acp load.........those reviews were done before the Civil War, hence the Minie Ball. Other than the .22BB rimfire cartridge no one loads a round ball for good reason. They are less accurate and inferior to conical bullets in every way. __________________ Need a FFL in Dallas/Plano/Allen/Frisco/McKinney ? Just EMAIL me. $20 transfers ($10 for CHL, active military,police,fire or schoolteachers) Plano, Texas...........the Gun Nut Capitol of Gun Culture, USA https://www.youtube.com/watch?v=pELwCqz2JfE

January 4, 2017, 02:16 AM	#7
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	As I stated in the OP, I feel that the shotgun adapter is more likely to be the most accurate because the barrel and chamber are made for a specific cartridge. The good news is my shotgun is an Over/Under and has a fixed rear sight and a fiber optic front, so that set up is much better than a simple bead, which I think is the issue people have accuracy wise with these adapters. I think I'm leaning towards the shotgun adapter. I can get it with a 10 inch length, which is perfect for .32 H&R Magnum or S&W Long, plus it'll be a short, thick barrel and give it plenty of rigidity and cut down on vibrations. I agree with you that it looks like this is something I'm just going to have to test out for myself because there are a lot of variables here based on others personal opinions and experiences. Guess it's time I make my own experience

January 4, 2017, 12:05 PM	#9
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	^ Testing to see what handloads give the best groups and once that's found using as a small game rifle that's not .22 LR.

January 9, 2017, 01:51 PM	#10
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	I want to update this thread for those who've been following it. I've been in email contact with Ace of MCA Sports, he makes shotgun adapters in 3 inch, 10 inch, and 18 inch lengths in a large variety of cartridge chambers as well as rifle adapters. There's a lot of information that's not on his website, such as whether the inserts are stainless steel or blued, if they're rifled (I assume for $100 they are rifled), for the rimmed cartridges if there is a recess or groove to dig a fingernail in and pull the spent case out, etc. I will post the answers I get when I get them. I do intend to buy one of these in .32 H&R Magnum as MCA Sports is the only company that makes a .32 caliber adapter. Once I get it in 8-12 weeks, I'll do a review on it with my shotgun and post pics of the targets and get more information on what's what with the potential accuracy on these adapters. For that review I have decided I will not use handloads and instead use factory S&W Long and H&R Magnum ammo because that's available to everyone.

January 9, 2017, 03:29 PM	#11
ShootistPRS Senior Member Join Date: January 3, 2017 Posts: 1,583	I have never seen rifle/pistol adapters for a shotgun but I can see the potential there. I have made chamber adapters for 12 ga. shotguns in 20 and 410 bore. The velocity is close to the same as if fired from a standard bore gun and patterns from a full choke 12 ga, with 410 cases does not differ much from a standard 410. My brother lives in a cabin that we built out in the country and he uses the 410 in his 12 ga. for rabbits and grouse. He does as well with the 410 as with the 12ga. It is cheaper to reload the 410 than it is to buy 12ga. or 410 shells. With a rifled insert accuracy would depend on the fit and repeatable indexing of the barrel. One might use o-rings to provide the proper fit and an extractor groove for proper indexing. while it might never be a target rifle it could be used for small and medium game or camp meat at close range. I'm sure it could be made more accurate with the application of a tapered retaining nut at the muzzle and an accurate fit at the breech. That kind of insert would have to be cut to the individual gun and not a mass produced piece like is being discussed here.

January 10, 2017, 02:01 PM	#18
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	^He's been replying to every email I've sent him. From posts on forums I've read made about MCA years ago, there were communication issues when people tried to contact him. From what I gather Ace works in construction, so Winter time is likely the best time to contact him, Summer time is worst. About indexing in the barrel, I plan to find which orientation the adapter works best in and scribing a line at 12 O'Clock. Ace mentioned this when I asked if he cuts a recess in the adapter to help remove the spent casing, he says he can do it, but believes it's best for one to test which position the adapter shoots best in and filing a groove or recess at 12 O'Clock and using that as the index position.

January 11, 2017, 04:28 AM	#19
kozak6 Senior Member Join Date: June 16, 2005 Location: AZ Posts: 3,113	Have you asked him what kind of accuracy to expect?

January 11, 2017, 07:39 PM	#20
johnwilliamson062 Junior member Join Date: May 16, 2008 Posts: 9,995	My understanding is the product itself is quite accurate. At least in examples where people have epoxied the tubes into hosts, which obviously defeats the purpose somewhat. Yes, I read a forum or blog post by someone at some point who did just that. The problem is entirely in the dimensions of the host gun chamber and barrel, which varies, combined with the orientation. I've not read a knowledgeable poster claiming the MCA product was out of spec, poorly finished or anything similar. One thing that has always baffled me is how these inserts can allow X39 to be safely fired through a 12ga shotgun. Almost 40,000 PSI difference between the two rounds.

January 12, 2017, 02:18 AM	#21
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	You forget that the adapter itself is a pretty thick piece of steel at the chamber of a 12 gauge shotgun.

January 12, 2017, 08:49 PM	#22
johnwilliamson062 Junior member Join Date: May 16, 2008 Posts: 9,995	True, but I don't think the hinges on most single shots are designed for those pressures. I know there are limits on what barrels could be attached to the H&R shotguns. Would an insert change that?

January 13, 2017, 02:37 AM	#23
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	I don't have the answer to that. I will say that when I asked if a .327 Magnum insert could be made, Ace of MCA Sports said that it was too hot for a shotgun, however he said that the .32 H&R Magnum adapter was capable of shooting the hottest Buffalo Bore had to offer, which is considered a +P load.

January 23, 2017, 02:24 PM	#24
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,883	Update, I received the adapter today, 2 months ahead of what is quoted on the mcace website. Here's a picture of the item: The OD turning has rough tool marks and a so-so finish that I can't tell is blued or black oxided, but the bore looks smooth as glass, which is what counts most. This is a 10 inch adapter and it has one O-ring close to the muzzle, other adapters I've seen that are a couple inches shorter have two O-rings closer to the chamber. I'm not sure what effect this will have on accuracy. Anyway, the insert fits very tight in the 12 gauge's bore. That one O-ring is doing it's job making sure the adapter won't rotate in the bore while the action is closed and it also is going to keep the gasses from going back into the 12 gauges chamber. I'll make another update on the .32 H&R adapter's performance when I get some trigger time at the range. I have a head cold at the moment, so this won't be for a week or two.

January 25, 2017, 01:12 PM	#25
natman Senior Member Join Date: June 24, 2008 Posts: 2,605	I played around with a 32 ACP adapter in a 30-30 single shot. There are a few issues with the rear loading adapter. As noted, accuracy is so-so. Rifle accuracy buffs fret over differences of a few thousandths of an inch of bullet jump; the adapter supplies full inches of bullet jump. The long jump before the bullet engages the rifling also affects ballistics because the bullet has so much free travel that the pressure never gets a chance to build up properly. By the time the bullet finally does engage the rifling, the powder is mostly burned. This results in a dirty burn and I suspect that velocity suffers as well. There are rifle adapters that put the pistol cartridge in front and have an internal firing pin. They are much more expensive and a lot slower to reload. A shotgun adapter with a properly dimensioned chamber and barrel would probably be more mechanically accurate, but this would be offset by the primitive sights found on most shotguns.

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