Barrel Lapping Setup

[BS]

I started lapping my rough 73 cal with a 1in72 twist. This is my setup.

I used 5/16 rod and threaded the ends. The brass insert is threaded thru, allows the rod and stub end to screw in. I used a ling bushing to push from one end, and into the brass insert. This expands both ends of the lead lap.[as needed]

I backed the nut and bushing off to show the shaft. I used a threaded shaft, my first try, but only the end with the nut would expand. I like this setup better.

The breech end is a hose watter fitting with a brass sleeve as a guide. The plastic ball could be bigger, but works OK.

I started with 320 grit Clovers Lapping Compound, but it is too fine, and am waiting for some 120 to come in.

I am fairly sure that most of the rough areas will clean up. Two of the groves have cutter chatter in three different areas. I am sure that is the cause of the two holes that blow thru the patches. Always two, and next to each other, just like the chattered rought spots.

As the lapping progresse, I will keep you updated.

Waiting for the shooting TEST!

It is so easy, I plan on doing my future barrels also. :thumbsup:

 

[J.D.]

That's a slick looking set up, and the lap looks pretty slick too. The first lap I poured had a lot of bugers in it and required recasting.

Did you smoke the bore to prevent the lap from sticking to the bore, or did you do someting else?

I wonder if mould resease agent would work to prevent the lap from adhereing to the barrel?
J.D.

 

[Bookie]

BS,You're on the right track! :thumbsup: The 120 grit will help a bunch. Glad to see that you shared this often over looked operational set up. Cheers, Bookie

 

[John Taylor]

The only thing I can see that could be added would be a bearing on your push/pull knob, looks great.

 

[John Vaccaro]

I worked for a barrel maker at one time. We made match grade HP barrels. We lapped with 180 grit, and once in a while at the customers request 280. Some of these barrels set 1000yd bench rest records. ML barrels shouldn't need to be laped finer than 280. Old barrels were "freshed" when they were "shot smooth". My opinion FWIW. John :thumbsup:

 

[BS]

My bearing is a red rag, works quite well. :grin:

I agree about the 180, but this rough one needs 120..........and the 320 is plenty fine too finish with.

 

[BS]

The barrel is back together. I will shoot it Friday or this Weekend.

Lapping cleaned up about half of the chatter marks, but the three loose spots are gone. :grin: [You could feel them when cleaning the barrel]

 

[mcgiiver]

Can you show us a picture of the actual lap, please.?

 

[BS]

Can you show us a picture of the actual lap, please.?

Top picture, center. This is one of them that I poured and used to lap my 73cal with. The sleeve pushes the lead lap aginst the brass 'nut', causing the lap to expand. I used three laps on this barrel.

Hope this answers your question.

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A little info:

I poured one lap without smoking the barrel with a candle.........the lap was not as smooth as the 'smoked' ones.

 

[BS]

Some of the test results:

Well they go down the bore easier.

My patched loads from pre-lapping don't shoot as well as before. :hmm:

Yesterday was windy, that might of had some to do with it, but.........

I did change lubes and get some better groups :grin: Still not great, but looks like I need some better weather.

Today was overcast and spitting rain:

Shot three patched balls with one of yesterdays[url] loads.....wide[/url] group.[windy too]

Made up some paper patches and used cream of wheat over the powder, It seem to help keep the gasses from going around the paper.

8 shots were in a 4.5" group at 100 yds. Two were high, two right, one up and left, and three in the middle.

80 FFF, semi-hard balls

 

[gmww]

I don't know the answer so thats why I'm asking this. After you've lapped the barrel is shooting a bunch of bullets through it needed to break it in like a new barrel? I noticed you said your groups opened up compared to before.

I wonder if your barrel needs to have a bunch of rounds through it for it to settle down. :hmm:

 

[J.D.]

Maybe a thicker patch, soft ball, or slightly larger ball. I don't know how much material you removed from your bore, but it may have been enough to require thicker patch or larger ball.

 

[BS]

Maybe a few..........can't hurt.

I am still getting one small hole blown thru the patch, I use to get two, so there is some improvement.

I have only shot three pure lead balls, some 705s and canvas patching. I may be able to use bigger balls and thinnner patches. :hmm:


Some more past history on paper patched balls.

At 50 yards, I shot some decent groups. [under 1.5"] then at 100 the same load wouldn't hit a 16" target. [1 out of three might]

Now I am shooting groups at 100 yds. with semi-hard lead balls.

 

[BS]

Maybe a thicker patch, soft ball, or slightly larger ball. I don't know how much material you removed from your bore, but it may have been enough to require thicker patch or larger ball.

Yep, that's what I am thinking also!

 

[BS]

Fired three paper patched balls today and the first had near the same point of impact as yesterday. Second shot formed a figure eight, third was left three inches. Drity barrel, one after another.

Spit wipe, two dry, then:
.725 PB/ pillow ticking lubed with castor oil and murphy's.

First two shots fromed another figure eight, the the third shot left about 3"s.

The best part is the condition of the pillow ticking, it lookes great, no holes or tears.

With some fine tuning, this may be a great shooter, it is very close.

I am using 80 FFF, I will try 70 and 90, then some 2F.

:yakyak: The first paper patched ball was .720 and 2.5 wraps of paper, it was supose to be 1.5.
It was really tight, good thing I have a 1/2" ramrod........it was very tight, but shot well and the rifling on the patch looked very even.

The second shot was 1.5 wraps....a loose fit, but shot the same as no.1.
Third shot was a freshly made tube, no time to dry... the shooting must continue! :grin: That might have something to do with the wandering left, then again, probably not. I am going to make some 2 wrappers for the .720 HBs. :yakyak:

And:.............did I tell you about the wind? That also could be the third shots left!......or I could be just hoping too much! :shocked2:

 

[BS]

I now have three load and patch combinations that shoot 3"s at 100 yds.

I was hoping to get in the 2 to 2.1/2" range. I may yet with some fine tuning. [also need better eyes]


My time in pulling the breech plug and lapping seemed to be well worth the effort........I shoot consistant groups, with the first and second shot in the same point of impact.

I can still feel the rough spots, but the patches are not torn..............now that I have the set-up, I plan on doing all my future barrels. :grin: