When the barrel(s) of a break-open single or double gun are fitted well at the hinge pin and standing breech, they are said to be 'on face'. As wear occurs in the hinge joint either from abrasion, overloading or just a lot of shooting, the barrels will begin to have a bit of clearance at the standing breech; they become 'off face'. Such a condition, once started, will rapidly accelerate as each round fired will have a running start to slam the barrels away from the standing breech. Repair is usually to build up and refit the hinge, typically a $200-$500 job.
Posts: 978 | Location: paradise with an ocean view | Registered: 09 April 2002
bpesteve, is very correct in his explanation. However, the "OFF FACE" condition caused by over pressure isn't so easy to fix, sometimes! This is because this OFF FACE CONDITION is off face due to the bending of the barr, and is actually still "ON FACE' at the bottom of the chamber end of the barrels, but OFF FACE at the top of the barrels. This is serious damage, and sometimes is beyond repair! this is why everyone keeps telling you to be very carefull about chamber pressure.
Posts: 14634 | Location: TEXAS | Registered: 08 June 2000
Quote: How many rounds on the average, before this is evident??? Maddog
As Eldeguello, says this isn't something that can be predicted with any certainty! However all loading should be started low, and worked up to in very small increments. The shooting off face caused by pressure can happen with the first shot, if the pressure is too high. The normal signs of pressure, that are accepted by most bolt rifle shooters, may not be evident in a double till the damage is already done. Those are flattened, or cratered primers, or brass transfere to the breech face. The best is to stay withing the load data that duplicates the factory ammo, or lower,and if a load shows any sign of difficulty in opening the rifle, back off immediatly, and pull the bullets, of any such loads.
The break top double rifle is not the place to go looking for higher velocity. Even if the rifle is new, and made of modern alloys, it is still 18th century technology, and the geometry is still the same today. Here, the effectiveness of the rounds used in double rifles should be a message to those who think they need high velocity to hunt large thick skined dangerous game. The old 450#2 NE with a 480 gr bullet speeding along at a modest 2175 fps, developes 5152 fpe @ muzzle, and only generates 30688 psi chamber pressure.
These slow bullets actually work better on things like cape buffalo than the fire breathing, heavy recoiling, things being sold today as something you simply must have or you will die a violent death at the horn of a buff. IMO, the biggest mistake most guys make when going to Africa is, thinking a 460 Wby, or the latest ULTRA, whiz bang, short, fat, beltless round that produces 60,000 psi chamber pressure, and 3000 fps with a 500 gr bullet, will kill like the hammer of Thor, when the only thing they are gaining is a sore shoulder, and a flinch from a cartridge that kills no better that that old 450#2 NE, and in some cases less as well! This mindset is also used to ruin fine doubles, by wanting to improve something that doesn't need improveing!
Posts: 14634 | Location: TEXAS | Registered: 08 June 2000
Since we are on the subject.... I am looking at getting either a Krieghoff or a Searcy, in 470 NE. In your opinions what will be better, since my knowledge is limited on these type of guns.
MAC; Thanks for the explanation, I do however understand balistics and am willing to stay within the limits of my chosen cal. I fully agree that these calibers have been working for many years and don't need improving. I have many of the new jacked up ultras,Weatherbys and such. But just finished a hunt in texas and used a old family hand me down 30-06 with great success. Thanks for everybodys in put, Please educate me more "Maddog"
Posts: 1899 | Location: Alaska | Registered: 03 May 2001
I agree with Mac,,,Also I much prefer the Searcy....
You can very easily shoot a double off the face with one shot in many circumstances. A good overload is all that is needed, same with headspace on a bolt gun...
Many English rifles come off the face at about 300 rounds and are still usable for several hundred more rounds..I always sent my gun in every year for whatever adjustment was needed, a phyical check up if you will and if you hunt a lot of dangerous game thats pretty good insurance, not expensive if you do it every year and don't let them wear out before maintence...
I frankly don't believe you can shoot the Searcy off the face with decent loadings..Argueably I belive that came about by steel that tended to wear much more than todays good steel..A searcy with ejectors opens like a English double with extractors, smooth and slick,..English guns wear in and by that process they also wear out, New English ejector guns were tight and hard to break open until until they wore in, for that reason many hunters of yesteryear took the ejectors out and used them as extractor guns. along with some other reasoning that may or may not have been legitamate.
Thats my opine, and its probably argueable...
Posts: 42321 | Location: Twin Falls, Idaho | Registered: 04 June 2000
