The Down Range Forum

Member Section => Down Range Cafe => Topic started by: 2HOW on August 03, 2012, 02:12:03 PM

Title: Short lane chamber adapters
Post by: 2HOW on August 03, 2012, 02:12:03 PM
anyone have any experience with these ? seems pretty easy and cheap.

http://www.gunadapters.com/
Title: Re: Short lane chamber adapters
Post by: MikeBjerum on August 03, 2012, 04:28:11 PM
I saw those several years ago and talked to my gunsmith while I was sitting in his shop listening to the meter ding ... I mean milling machine adjust my gun.  He is ok with the full length inserts (cartridge insert into a shotgun barrel), and he will accept the changing of shotshell inserts, but he had some choice words concerning sending a slug or bullet down an oversize tube.

His belief is that it is true these mfgs go through testing for insurance, but that doesn't mean that are truly firearm safe.  If you want something different, buy it!  Guns are too expensive, and people are too valuable to cheap out!
Title: Re: Short lane chamber adapters
Post by: Big Frank on August 03, 2012, 05:16:04 PM
I made one out of a cut down pistol barrel glued into a shotgun shell. It worked until the epoxy started to come loose, then I threw it away. I wouldn't reccomend anyone else make their own but I don't see why these wouldn't work as they are supposed to.
Title: Re: Short lane chamber adapters
Post by: tombogan03884 on August 03, 2012, 06:31:15 PM
Seems like a bad idea.
Whether they are safe at the chamber end really doesn't matter since accuracy has to suck.
When a bullet leaves the muzzle it starts to rise, that's what it's going to do when it leaves the insert, then it will hit the top of the bore and more or less just rattle down the pipe.
Something like 7.62 X 39 to 7.62 x 25, or 30-06 to 308 might be practical, but these are just going to wreck a shotgun barrel.
Title: Re: Short lane chamber adapters
Post by: bjtraz on August 03, 2012, 09:30:48 PM
Seems like a bad idea.
Whether they are safe at the chamber end really doesn't matter since accuracy has to suck.
When a bullet leaves the muzzle it starts to rise, that's what it's going to do when it leaves the insert, then it will hit the top of the bore and more or less just rattle down the pipe.
Something like 7.62 X 39 to 7.62 x 25, or 30-06 to 308 might be practical, but these are just going to wreck a shotgun barrel.

This is a physical impossibility, and an old wives tale. It appears the bullet rises, as the difference from bore axis to sighting system, causes the barrel to be tilted up, in relation to the line of sight is straighter. Our friend, gravity, begins it's pull as soon as support is removed. If you doubt, check with any physics major.

Brian
Title: Re: Short lane chamber adapters
Post by: tombogan03884 on August 03, 2012, 09:37:14 PM
This is a physical impossibility, and an old wives tale. It appears the bullet rises, as the difference from bore axis to sighting system, causes the barrel to be tilted up, in relation to the line of sight is straighter. Our friend, gravity, begins it's pull as soon as support is removed. If you doubt, check with any physics major.

Brian

You're forgetting that bullets are aerodynamically shaped and therefore generate a certain amount of lift from their initial velocity.
Ask any aerodynamics major.
That aside it changes my point about the barrel damage how ?
Title: Re: Short lane chamber adapters
Post by: kmitch200 on August 03, 2012, 11:30:24 PM
You're forgetting that bullets are aerodynamically shaped and therefore generate a certain amount of lift from their initial velocity.
Ask any aerodynamics major.
That aside it changes my point about the barrel damage how ?

Ummm, no.

Bullets are symmetrical - there is no aerodynamic rise. The forces act on all sides of the bullet equally so - no lift. Gravity will do it's thing like always.
Bullet yaw could theoretically cause some lift but the very next 1/2 rotation would negate that pushing it the other way.
Any Magnus Effect could just as easily push the bullet down as up depending on L or R rifling twist and L or R wind.

As far as barrel damage, these things have been around for over 30 years from various companies and I haven't heard of any barrel damage - doesn't mean that it hasn't happened - YMMV.
If the company can make the insert straight, there is no reason for a bullet to suddenly veer off course just because it is now in a larger tube.
If that were the case, suppressors wouldn't function for more than 1 shot.

I never bought one only because I think it would be a PITA to reload the insert. That's the only thing that stopped me decades ago. (back then they were a little more pricey too)
Keeping one or two around might make sense in a TEOTWAWKI situation. If you run out of shotgun ammo you could have a single shot with *some* caliber rather than an empty boat oar.
Title: Re: Short lane chamber adapters
Post by: Timothy on August 04, 2012, 08:53:02 AM
Gotta agree with kmitch and bjt on bullet rise.

The aerodynamics of bullet design are to make it stable and the bullet will never rise above the bore axis in flight.  Since it's symmetrical, as kmitch mentions, the physics of lift are negated as the flow of air passing the bullet is symmetric as well.  There is no high or low pressure wave on the bullet required for lift per Newtons second and third laws or Bernoulli's principle.  It is not an airfoil or wing.
Title: Re: Short lane chamber adapters
Post by: Ichiban on August 04, 2012, 09:27:37 AM
Aren't you essentially turning your shotgun into a derringer doing this?  This seems like a solution in search of a problem.
Title: Re: Short lane chamber adapters
Post by: Big Frank on August 04, 2012, 02:32:10 PM
You can use a pistol caliber without carrying a pistol. I think it would be good for a coup de grace.
Title: Re: Short lane chamber adapters
Post by: Solus on August 04, 2012, 02:44:51 PM
Aren't you essentially turning your shotgun into a derringer doing this?  This seems like a solution in search of a problem.

They have an 8" barrel, so not a derringer, but a long barreled pistol...that will be easier to aim and control.

I don't know the ballistics dynamics, but that still leaves 8" or more of "free flight" inside the shotgun barrel where gravity and recoil will be at work.

Title: Re: Short lane chamber adapters
Post by: TAB on August 04, 2012, 06:14:59 PM
I would be worried about the barrel.  Shot gun barrels are very thin. A little bit of flame cutting and you could have a shot gun barrel coming apart.    also what m 58 said about a death blow, would most likly not be legal in states that have smooth bore only rules.