Vent liner

[little joe]

I,m going to share a embarresing event with you but I hope this helps someone else. Last week at the range I was shooting a A weight X 36 cal. rifle.Having a good time with a good friend we were relaxed. I shot at the target with some extra recoil, and two holes appeared. I reloaded and then started to prime and my vent liner was gone, nothing hurt but my pride.  The liner had sheared and left 3 threads of liner in the barrel. Here is my thoughts, one I think I charged powder ball and powder ball hence 2 holes. The liner I probably over tightened with vise grips. If I only had 1 charge in the rifle I don,t think the white lightning liner would have failed. Two mistakes come together and you have  the  potential for an accident. Lesson learned, pay attention to what you are doing. I,m a careful shooter but I dropped my guard on this one. As to the liner I used vise grips to install and probably  over tightned it. In the future I will hack saw a screwdriver slot in the lug  so I will not over torque it.Hopes this helps someone.

[LH]

Stuff breaks sometimes.  Glad it didn't hit anything important.  That's certainly an odd occurrence,  I never would have thought one would separate like that,  but anything can happen.  You mentioned that you thought you over tightened it, was the back half of it hitting the side of the breech plug so the touch hole was on the face of it? 

[little joe]

The touch hole was 5/32 of in. in front of the face of the face of the plug.

[Dphariss]

I,m going to share a embarresing event with you but I hope this helps someone else. Last week at the range I was shooting a A weight X 36 cal. rifle.Having a good time with a good friend we were relaxed. I shot at the target with some extra recoil, and two holes appeared. I reloaded and then started to prime and my vent liner was gone, nothing hurt but my pride.  The liner had sheared and left 3 threads of liner in the barrel. Here is my thoughts, one I think I charged powder ball and powder ball hence 2 holes. The liner I probably over tightened with vise grips. If I only had 1 charge in the rifle I don,t think the white lightning liner would have failed. Two mistakes come together and you have  the  potential for an accident. Lesson learned, pay attention to what you are doing. I,m a careful shooter but I dropped my guard on this one. As to the liner I used vise grips to install and probably  over tightned it. In the future I will hack saw a screwdriver slot in the lug  so I will not over torque it.Hopes this helps someone.

What was the proof load when the barrel was proved?
This was a material failure if it left threads in the barrel. So a proof load should have been revealed this without threat of personal injury as occurs when there is a failure when in actual use.

Dan
 

[smylee grouch]

I wonder if using a just slightly oversize drill bit when you drilled for the vent would contribute to the outcome.

[D. Taylor Sapergia]

How many threads of the liner were fully engaged in the wall of the "A" weight .36 cal barrel?  Many years ago, I installed a drum in a 13/16" x .45 cal. barrel, and it blew out.  Valuable lesson learned!  For one thing, I no longer use customer supplied parts for one of my builds, and I make sure the barrel wall is heavy enough to support the insert.  If it is not, the barrel gets a patent breech like the ones Dan makes.  I don't sleep well enough at night now, without that sort of thing haunting me.

[Bob Roller]

For drums,I used a drill at least ONE size smaller that the drill charts recommended and I did the same on vent liners.
Countersink the hole the depth of ONE full thread and try and use a new,sharp tap and a bit of tapping fluid.I use rapid
tap and have good results.

Bob Roller

[gwill]

Ok this has got me thinking about my new barrel. I installed a white lightning liner over the weekend using the drill and tap that came with it. Followed the instructions. It turned out ok. The barrel has plenty of thickness. And all of the threads engaged.  So what do I do to avoid an issue like this. Proof with a double powder load and a single ball followed by a single powder load and two balls?  What do you think?  Thanks for your help.

[Dphariss]

Ok this has got me thinking about my new barrel. I installed a white lightning liner over the weekend using the drill and tap that came with it. Followed the instructions. It turned out ok. The barrel has plenty of thickness. And all of the threads engaged.  So what do I do to avoid an issue like this. Proof with a double powder load and a single ball followed by a single powder load and two balls?  What do you think?  Thanks for your help.

I shoot a normal load through the barrel than a double service charge with double ball.

Dan

[little joe]

Proof load was 50 grs. fff  .350 ball and .018 ticking 5shots. My openion was I.ll never be shooting more than 25-30 grs of powder so I,m safe and was until I double loaded it. I will still use the white lightning liner but I will cut a screwdriver slot to take no chance of over tightning it. The wall thickness at the liner was .275 which is good in my openion. Take Care

[Dphariss]

Proving needs to be realistic based on what the rifle might like for an accuracy load. Some shooters use as much as 70 gr in a 40 for accuracy loads for example. So in this case the proof needs to be a significant overload for 70 gr in a 40. Given that many seem to shoot 50 gr or so 100 would be a minimum.
But many here seem to settle on a load with little concern for accuracy. Or they expect too little from the rifle.
In calm conditions a decent rifle barrel should keep all holes touching a 50 yards. Hard to where I live (15 gusts to 20+ right now) but realistic in many places.
I have both ML and BL loads to test but its pointless and has been every day I could go out to shoot

In any event a great many people shoot loads that are too light to be really accurate in many rifles.
I would love to find the British Proof levels for rifles with a RB but its hard to find it would seem so I use the double powder/double ball as I always have. I have yet to have anything come adrift.
This is a 58 proof load.

Yeah I like to video them.

Dan

[Jerry V Lape]

Dan,

I haven't found my reference to British proof loads  ub Austria Laws of 1929 for black powder firearms specifies for bores between 12.4 and 13.4 mm (.488-.53 caliber) the 1st proof of the barrel of a rifle as 9.4grams powder, 12mm thick bore dia wad and 42grams of shot (not a slug or ball).  This would be 145grains of powder and 648grains of shot (approx 1 1/2oz).  Powder was #1 Fine hunting and target black powder.  So some good quality powder in  FFFg would probably be appropriate. 

The second proof, which came once the rifle was completed used 7.1grams of same powder and again 42grams of shot over the 12 mm thick wad.  Equals 109.5grains of powder and 1.481 oz of shot. 

These were not as potent as the German laws of 1891 which for a 11.18mm-14.66mm bores were 16.5grams powder, wad, 46.3grams of shot for 1st proove, 2d proof was 11grams powder/46.3grams shot for a service load of 5.5grams powder/34.7grams shot.  The service load for a .54Cal rifle would have been 5.5grams powder/34.7grams shot.  Equals about what would have been a good load for the .45-90 rifle. 

German proofs were known to be stiffer than the other European countries.  But even the Germans were not doing double powder and double ball.  They were at double powder but only 130% on the projectile weight for the second proof which was pretty much the barrel condition you would be testing with finished barrel, breech plug,  final contours and the various dovetails and cuts in the barrel metal.  The first proof would be on uncontoured barrel with no metal cuts and breeched with a plug clamped in place by the proof house (unthreaded ). 

I will look some more for the British proofs, know I have them somewhere. 

[FlintFan]

As to the liner I used vise grips to install and probably  over tightned it. In the future I will hack saw a screwdriver slot in the lug  so I will not over torque it.Hopes this helps someone.

I would agree with your theory.  I have heard of this happen before with White Lightnin liners, even so far as a person telling me that they have sheared one off at installation.  I believe that case involved the gun builder using far too much torque when installing the liner, and don't believe the liner was in anyway at fault or defective.  It is very hard for many people to judge just how much torque they are applying with a vise grips.  Too much torque can cause the liner (or any other kind of threaded fastener for that matter) to stretch, crack, etc. under the head.  Your plan of making a screwdriver slot is a very good idea.  It will be more difficult to over tighten the liner using a screwdriver. 

[Dphariss]

Dan,

I haven't found my reference to British proof loads  ub Austria Laws of 1929 for black powder firearms specifies for bores between 12.4 and 13.4 mm (.488-.53 caliber) the 1st proof of the barrel of a rifle as 9.4grams powder, 12mm thick bore dia wad and 42grams of shot (not a slug or ball).  This would be 145grains of powder and 648grains of shot (approx 1 1/2oz).  Powder was #1 Fine hunting and target black powder.  So some good quality powder in  FFFg would probably be appropriate. 

The second proof, which came once the rifle was completed used 7.1grams of same powder and again 42grams of shot over the 12 mm thick wad.  Equals 109.5grains of powder and 1.481 oz of shot. 

These were not as potent as the German laws of 1891 which for a 11.18mm-14.66mm bores were 16.5grams powder, wad, 46.3grams of shot for 1st proove, 2d proof was 11grams powder/46.3grams shot for a service load of 5.5grams powder/34.7grams shot.  The service load for a .54Cal rifle would have been 5.5grams powder/34.7grams shot.  Equals about what would have been a good load for the .45-90 rifle. 

German proofs were known to be stiffer than the other European countries.  But even the Germans were not doing double powder and double ball.  They were at double powder but only 130% on the projectile weight for the second proof which was pretty much the barrel condition you would be testing with finished barrel, breech plug,  final contours and the various dovetails and cuts in the barrel metal.  The first proof would be on uncontoured barrel with no metal cuts and breeched with a plug clamped in place by the proof house (unthreaded ). 

I will look some more for the British proofs, know I have them somewhere. 

Double ball in a 54 caliber rifle is only about one ounce of lead. 
The British used a lead slug for proof from what I see in Greener.
Most proof houses, or so I have read, used powder that was fine grained and fast chemically.
The only rifle info in Greeners "The Gun and Its Development" 1896 is  a 507 grain bullet and 174 gr of powder for a .400 bore.
The is the table for "...Rifled Small Arms of every description except those of the 8th class and definitive proof of the 7th class..." The proof for the 8th class is 170 gr of powder and a 293 gr bullet. I have no data on the 7th class.
The unrifled arms of .453 caliber used a 122 gr bullet and 150 grains of powder for "first class".
Breech loading shotguns of 30-32 bore used 164 gr of powder and 194-207 gr bullets.
Given this information in Greener I feel that a 40 proved with 100-140 gr of powder and 186 grains of lead is perfectly reasonable for a 40. 200 powder and 440 lead is OK for 54s.
With the barrel steels I use, that I know will stand smokeless proofs in the 50000 to 70000+ range I doubt that a perhaps 25000 proof shot with BP is going to strain anything.
So far as blowing out a breechplug. Calculate the area of the breech exposed to the powder gases. Say a 40 cal with the grooves to .420 has as a breech face area of something less than .138 square inches. So if we take 25000 times .138 we get 3450 pounds. Now this is probably excessive since I doubt the proof load will make 20000. Then we look at the tensile of the weakest steel bolt we can find. The proof load, if I understand the terminology properly, is about 14100 for a grade 2, 5/8-18 bolt.  In a quick search I found not data for grade one but the material is the same as grade 2 it seems.
See http://www.almabolt.com/pages/catalog/bolts/proofloadtensile.htm
So unless the threads are VERY short, its going to be tough to blow out a breech plug even a 5/8-18 in a 50 cal.
There are people who post here more qualified to comment on this than I but I believe that this is fundamentally correct in the math.

Dan

[Jerry V Lape]

Dan,

The table of proof loads which gives you the .40 cal at 170grains powder and 507 grains lead slug for definitive proof gives the .54 a proof load of 170grains of powder and 715 grain slug.  Every caliber from .40 to .70 used 170grains of powder and got the pressure by upping the slug weight from 507 grain to 1077 grains in incremental steps. 

[Dphariss]

Dan,

The table of proof loads which gives you the .40 cal at 170grains powder and 507 grains lead slug for definitive proof gives the .54 a proof load of 170grains of powder and 715 grain slug.  Every caliber from .40 to .70 used 170grains of powder and got the pressure by upping the slug weight from 507 grain to 1077 grains in incremental steps.  

I was quoting the Provisional proof table the one that REALLY MATTERS. In this case the .700 bore size uses 252 gr of powder and 1077 slug.
In this case the service powder charge is 85 grains, the "ball" for the .700 is 808 grains. So they use THREE TIMES THE POWDER for the .700 and the service projectile is about 75% of the proof bullet.
 
As near as I can tell from a quick look at the explanation of the rules pgs 280 onward in my copy the RIFLES we make would be arms of the Second class OR the 7th Class (Express rifles). ALL barrels must pass PROVISIONAL PROOF with perhaps some very few exceptions. So since the barrels I use have never been provisionally proved OR EVEN PROPERLY PREPARED FOR PROOF, I assume the provisional proof is the correct one. Given the information I have this would be 205 gr of fine grained powder and more than 3 BALL WEIGHTS OF LEAD in the .540 bore size. So tell me how it is that I am wrong with 200 gr powder and 460 gr of lead? How is this excessive? My reading is that its actually DEFICIENT by about 255 grains of lead and a few grains of powder .
I would also point out that the proof levels I have listed here DO CERTAINLY apply to RIFLED arms of the SECOND CLASS. But if the rifle uses a heavier powder charge than normal, and most people do today in RB MLs AND bullet guns THEN the maker must send in the service load with the barrel so that the Proof House can ADJUST THE PROOF accordingly.

Frankly I do not care what the Europeans on the Continent used for proof. Some guns imported with Continental proof marks would fail when proved by the British according to my reading.
So I use the British as a guide but as I have stated my proof levels are actually LOW.
But unlike some here some of whom insist proving is a waste of time none of my guns have had failures in service.
If this post not understood or if it is then further explanation on my part is pointless.

Dan

[Jerry V Lape]

Dan,

In my latest reply I thought I was agreeing with you.  The definitive proof you quoted from Greener for the .40 cal iis the same table I was reading and I added in the data for the .70 to show how they used increased projectile weight to maintain a similar level of pressure in the larger bore, while holding the powder constant over such a broad range of calibers.  I found that interesting.

 I do think we do not need to use the provisional proof loads as they were done on barrels that were not finished exterior or interior and had no breech installed.  The reason they dropped the 2d proof (definitive proof) loads was in recognition of having a barrel in a less robust state and in a fully assembled rifle which now involved possible damage to stock etc.  Rifles the members of this board produce come closer to fitting the definitive condition in my opinion than a rough barrel tube which hasn't reached final dimensions.