Proofing an old shotgun barrel

[exMember]

Looks like that old 41 1/2" long 12ga is going to live again! Tomorrow I am taking it to a gunsmith and having him thread a new over sized nipple for it.

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[Marty1]

8) vid.  Do you know what the load was :?:

 

[exMember]

yes its 100gr 2fg gearheart owen black powder, 480gr worth of buckshot. When I get a round ball mould it will be 492gr so I wanted to test with a load similar.

 

[Sparkitoff1]

I am an English trained gunmaker (Ret) so I have extensive training and experience with proof processes. Your method is sort of a unique take on how it is done and it certainly works. However, a proofing is done with an "over-charge". If you are going to load 50 grains then this might be a "proof". Explained crudely, the proof load is twice the maximum amount of powder you would normally use. Nowadays with technology it is essentially twice the maximum pressure you would get from the most "powerful" commonly available load. I would think with that gun you would load somewhere around 70 or 80 grains of powder. With that in mind, you have neither a "double-charge" nor a "double-pressure" load that you tested with. I appreciate your enthusiasm and I like your ingenuity!  I am not convinced that barrel is perfectly safe with that one blast. I'd like to see it work out for you, so be careful and somewhat reserved as you proceed.

 

[exMember]

i fired 3 shots total, 2 on video. Also with this being an antique barrel with zero info, we have no clue what max load is and with it being so old, i dont think any one of us would consider shouldering it with a max load, even if we knew what it was.

 

[Marty1]

In "general", I always understood a proof load to be much more than one would ever shoot out of the particular firearm.  


FG, how many grains of powder do you plan to use when you hunt with it :?:

 

[mark1945]

I dont know if its still in the Dixie catalog but there used to be a chart showing the proof loads used back then for different gauges and calibers used in Belgium I think. I used it years ago on a sxs 11 gauge barrels a friend gave to me. Decided to check before I made a stock and hunted down locks and triggers for it. It called for 300 grain 2f and equal shot by volume set of both barrels with a cannon fuse tied to a tree and they survived . Still have the barrels but have never finished the shotgun yet.

 

[exMember]

I asked the gunsmith today about the double load and his eyes just about popped out of his head lol. He said that 100gr charge was plenty due to the age. You guys with these 300gr charges are talking about NEW barrels, not something that is 150+ years old.

Marty, Most likely in the 70gr range with a round ball.

Also, when the new nipple is in, he said to go ahead and test it again.

I showed him what the gunstock builder did and explained what i found and he was just chuckling over it.

He didn't seem to have an issues with the barrel being shot at all.