Barrel laping

[Rebel Dave]

What are some of the ways to lap out a rough barrel. I have one that tears patches when you run one up and down with a cleaning rod. This is on a N.I.B. , J.P. Murray carbine, that I got for a song and a dance. I am going to play around with it and see how well I canget it to shoot.

Thanks, Rebel Dave (still unreconstructed)

[Charlie Hahn]

This needs to be a step by step process. I would suggest that you pull the breech plug and see if the lands or grooves have the issue. I suspect that you will see that the new barrel has burrs on the edge of the groove and might be able to be removed by shooting. Usually this could take 100 rounds or so with cleaning every 5 or so shots. Below are two other ways to lap the bore. These are very basic steps, and would suggest that you request help from either a machinist, or gun smith to help with this.

Controled Process:

First make a brass lap that is at bore size, and use this with some fine lapping compound to remove any burrs pushed up from the rifling process. The lap is pushed through the bore with light oil until you have 100% contact. At this point try the patch and see if the issue has gone away.

If not, you will need to make a rod that can be used to cast a hard lead plug in the bore, Cerosafe can also be used for this. From the front of the barrel, you need to make a plug to block the bore about 1 inch down. Position the rod in the bore and pour lead into the barrel. When cool, slide the lead plug out about 3/4 inch. Charge with lapping compound and pass this through the bore several times to smooth the land and grooves.

You may need to repeat this step several times depending on how bad the bore is.

Fire lapping:

If you determine that the bore is not too rough, You might consdier fire lapping the bore. This is done using fine lapping compound, (400 to 600 grit) rolled onto a mini ball, and loaded and fired. Again you will need to check the bore condition as you do this.

Charlie

[Ken Hansgen, 11094]

Dave, See Dennis's (macvcallsign) Apr 20, 2008, post to the "Hoyt Barrel Question" thread for Bill Large's recommendation.

[macvcallsign]

Hi Dave,

I had a Murray many yrs ago and as I recall it had shallow but very sharp edges on the grooves, also riped the patches. I just used my old standby method of shooting a couple of hundred rounds thru it and the roughness did go away. Shot pretty good, had to use the Lyman 575213 New Style Minie with 42 grs of 3F. Found this info in my old notes from 30 yrs ago.

Was never really satisfied with it though, It did need some serious Lock work and probably Glass bedding too.

Well, I went to the Extreme and had Bill Large put a Barrel on it!
:lol: :lol: Shot much better than! :) The only problem than was that primitive block sight. Too much bother at 100yds. Ended up selling it to an N-SSA member maybe 5-6 yrs ago. Never did hear how he did with it though?

Anyway Dave, that's my experience with the Murray. I'm sure it will work, just have the "stick-to-itness"

Chao,

Dennis

[Rebel Dave]

Many thanks to all who replied.

I geuss i have A little work cut out for me.

Dennis... I plan on glass bedding the barrel, soon. I made a new sight blank for the rear, it is 3/8th in high from the base of the sight. It will be a peep sight. I also added 1/4 in to the front sight. I just have to figure out where to drill the whole for the peep.

The lock is not to bad on this murray, it has a strong main spring. I polished all the parts and smoothed the rough surfaces of the main spring. I also soldered some brass shim stock on the tumbler, and got the trigger pull down to 4 lbs. I always use silver solder. I also re-hardened the sear and tumbler, in kasenite.

The one thing I'm not sure of is the comb on the stock, it has a funny shape, and I'm don't know if theres enough wood to reshape it correctly.

This is my first project after a long hiatus from skirmishing. I am kind of working my way back in. Hope i can make the natiionals in the fall.

Once again thanks to all who repied.

Rebel Dave (still unreconstucted)

[macvcallsign]

Dave,

Sounds like you are on the right track. Check the specs with the small arms people to see if and how much you can play with the stock measurements. maybe send an e-mail to John Holland, he would know since he is the head guru of the small arms committee, he is a very knowledgeable young guy lol, and give you great guidance to do the job right.

Good luck,

Dennis