how to check the bore

[art_collector]

Hi,

Just wanted to know if there is any instrument available to check the bore size. I have seen a couple of single shot rifles by Lyon & Lyon etc entered as NPB Rifles on licences. One of them the licence told me is a 22 hornet but the bore looks to be much bigger.

AC

[eljefe]

AC, no instrument available as such here,
simple method is to block the barrel ahead of the chamber using some clean , non oily rag.
melt and pour sulphur into the chamber from the breech end.let it cool off and gently knock it free using a ram rod type of rod from the barrel end-AFTER removing the initial cloth used as stopper!
if you can get it from USA, Cerrosafe is a very acceptable and universally used lead alloy used for this chambercasting.
Please be advised that you must use proper respiratory and eye/hand protection /care while doing this and I am not liable for any injury/ mishap suffered by you in case you follow the advise given above/during the procedure
Enjoy
Axx

[snIPer]

wouldn't a simple screw gauge suffice?

[Lenny]

A vernier caliper would also do the job with out the hassels

[cottage cheese]

Hi- The calipers and screw gauge will only tell you the size of the bore. If you need to know what the particular ammunition is,... well you'll have to start off with a chamber cast as eljefe suggested.... then do the finding out based on dimensions derived from the casting.... that should keep you from getting bored...

[Mark]

Asif has it correct, the ONLY way to make an accurate decision is to do a chamber cast.

A couple additional hints-

Use a piece of paper towel, and push it about 1/4" into the bore.

Warm the chamber, which can be simple as leaving it in the sun for a while, or using your wifes hair dryer on it. It should not be hot, but if it feels warm to the touch it helps get an even cast.

I make a little melting cup with a pour spout from an aluminum beverage can. It does not have to look pretty. Cut the bottom out of the can to leave a 3/8" high side, do not cut all the way around the can but leave a 1/2" wide "handle" that extends straight up for 2 or 3 inches and also another inverted V that will be a pouring spout.

Clamp the rifle in a vertical position, with the muzzle facing downwards and then start trimming the pour spout of the cup until it is short but still allows you to pour the sulphur into the chamber.

Lightly oil the chamber. Some oil on a cotton swab is all you need.

Sulphur is cheap enough, better to have a bit too much than not enough but 2 tablespoons will be plenty.

When you pour it, STOP when it is level with the chamber. I don't really need to tell you that because even though everyone says it I bet most people still let it overflow and then you spend 30 minutes with a dental pick, picking tiny bits of sulphur out of the recesses in the action.

Heat the sulphur just enough to melt it. it does not need to smoke. an alcohol lamp works fine, as I bet a candle would too. As Asif say, don't breathe the smoke! A fan behind you helps, it does not have to be a hurricane just an almost imperceptable breeze.

When the sulphur has hardened, try to knock it out with a firm tap. Have a towel underneath the action to catch the casting, that way you can concentrate on just popping it out.

If you mess up, just try it again!


LOL, am I a packrat or what- I just checked and I still have the last can I cut up into a melting cup! It gets bad when I don't toss a cut-up pop can! Anyway, I'll take a picture of it later so you can see a home made pouring cup.