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12-23-2012, 12:44 PM #1
Anyone made a small caliber insert for a shotgun barrel?
I was thinking about making a .22 Hornet insert for a small side by side shotgun, finding a .223 take off barrel with 1:14 or 1:16 twist, thinning the barrel a ways down from the chamber to near-minimum diameter and fitting it in an aluminum sleeve similar to those made by Briley to support the rifle barrel within the shotgun barrel.
Seems like a fun project - any thoughts?
12-23-2012, 02:26 PM #2
Sounds better than the stubby .22LR/SG inserts that are no more than a very short barrel anchored at the breech and offset for the FP. (odd report when firing ..) Selectable or double trigger(s) would be tops, obviously. Bullet weight options in .22H are limited and twist shouldn't be too critical, so how about a 1:12" twist .223 tube that should be easy to find? The centering sleeve is a great idea, & IMO 'Hornet' is worthy of a full length tube. What'd make this all so easy is going for a rimmed case to adapt to, tho' extraction will require some forethought, design tweaking.
Although .22H's MAP is below 45k (CIP PSI [piezo], SAAMI CUP) I'm not sure I'd do this for a .410 due to resulting chamber-wall thickness of your insert, but as usual depending on the SG it's made for. In a 16 or 20Ga this could become a nice 'yote buster beside a buckshot load, and without the range/choke constraints. btw: I've had many pass-throughs on 'yotes at <100yd with .22 Mag but find .22H less critical of shot placement when shooting off-hand. Whatever you're planning this for I say Go for it.
12-26-2012, 03:31 PM #3
I think you will be hard pressed to find a .223 takeoff in 1:16. You might find one in 1:14. AR barrels will be faster twist unless really old.
The Hornet body diameter is about .296" so your overall chamber diameter should be around .700" which is going to be about an exact fit for 20 gauge (.698" at rear of chamber.) Anything smaller would be relying on the shotgun chamber to carry part of the pressure load and I think that is not a good idea when you are talking about barrels designed for shotshell pressures. It might be safe in a 28 gauge (.627" chamber diameter) but definitely not in a .410.
12-27-2012, 08:38 AM #4
Thanks - I appreciate the advice. I'd read an article somewhere in which the author recommended not going above a cartridge like the hornet with an insert as the lock-up in most side-by-side shotguns wasn't designed for the forces of a centerfire cartridge. I've seen Krieghoff drillings with sub-caliber inserts up to 7x57 but those were designed with that purpose in mind. I'll be hitting a big gun show nearby the first weekend in Jan and will look for an inexpensive shotgun to experiment with.
12-27-2012, 12:15 PM #5
Its a foregone conclusion that doing this in some of the old, brittle case iron receivers is probably not a good idea but even those old receivers in 22 hornet would probably be perfectly safe. But why would you? Break actions are notoriously inaccurate, hard to mount scopes to and have poor triggers. As a novelty, if you want to put money into something with no expected return, why not? Just remember you will probably have to re-sight the gun every time you put in the insert. Unless you make the insert permanent. That's why simple to make inserts have never become populare. The idea has been done to death with ZERO success beyond novelty.
12-27-2012, 02:24 PM #6
Well, there you have it folks - once again the definitive response to tomfoolery. For example, WTF does Krieghoff know about reinforced fences, supplemental locking mechanisms, and shotgun barrel inserts from .22 mag to 9.3x74R as an option to a firearm which starts at $22K before any adornment or accessories? Europeans, Germans in particular, are notorious suckers for poorly built firearms and willing to put up with horrible accuracy, balky triggers, etc., and still pay through the nose for the privilege. Ach du lieber Gott!
Krieghoff International - CLASSIC Double Rifle
By your leave, sir, I'll be buying a cheap shotgun to experiment on because I don't want to risk damaging my Kolar or popping the ribs on my vintage field guns. As I said initially, a fun project which I'll do as a learning exercise.
Breathe in, breathe out.
12-27-2012, 03:49 PM #7
Yup those junky European single and double rifles, and drillings, chambered in all calibers, must be junky weak German crap..
Blaser Model K770 is available from factory in 300 Weatherby.. A known putt putt low pressure cartridge.
They have had insert barrels Einstecklauf ( Krieghoff, Blaser, System B. Fritz, Princess... last 3 available in .22 Hornet) that are actually fitted to each chamber, (and are adjustable as to POI by nice sliding tapers..)
More cheap junk... Never works... Oh wait.. These are are all inspected/Proofed by German proofhouses, and factory sighted. With test targets delivered with gun.
And most of these guns can be custom ordered in any caliber... Extra price for rimless cartridges.. Little more work on extractor system..
The double set (feinstecher) triggers are also know to be junk.. 3.5 or less trigger pulls, crisp as glass always... Terrible..
Not everyone is in the Canadian bush.. And some can actually afford to buy a quality rifle...
There were actually a couple of modern US attempts to build a decent break open rifle. The TCR 87... Of course crappy TC barrels don't help..
As to a Hornet in a standard cheap Break open.. No one has mentioned the little itty bitty problem of firing pin diameter.. Large pins WILL allow primer flowback or worse..
A proper rifle caliber break open, will have a High pressure cartridge sized firing pin, not a .100 shotgun primer sized one, in a sloppy hole...
12-27-2012, 03:54 PM #8
I know people that use Krieghoff rifles and inserts. Perfectly safe, like I previously stated. They still don't return to zero. Within 2 to 20 inches depending on machining practices and common sense at 100 or 200 yards for most systems like that. I think Kriegoff says 1.5 inch's at 100 yards but you pay dearly for it. They cut everything on centers from the start to finish and regulate the gun with offset cams in the muzzle. A very complicated , hands on, expensive system. The Kriegoff system is semi permanent. No reason that you can`t reproduce it and have it work as well as theirs.
12-27-2012, 04:18 PM #9
12-27-2012, 05:51 PM #10
I think Krieghoff has no firing pin problems because they locate everything on centers before they make the gun. Just like any other modern manufacture would. Its simple mathematics.
A lot of people want drawings to cut barrel extensions and make actions while most of us just reach for pencils. Its just mathematics. Rifle firing pin tips start at about .050 to keep primers from rupturing an leaking back. Shotguns use up to .110 and smaller because of low pressure and miss alignment problems related to break action guns. Small diameter rifle firing pins work perfectly well on shotgun primers so long as they hit center. Don`t confuse machining and manufacturing practices of 20 or 60 years ago with today. The USA, The Union of Soviet Socialist Republics , China and a host of other countries have atomic capabilities now. A lot of things have chanced, dontchaknow!
12-27-2012, 07:04 PM #11
If just a personal exercise for the joy of it then go ahead and show us all how you did it. But for the various reasons already stated the idea is an impractical one.