Slug a Barrel

[ArtinNC]

Been reading about slug barrels , So I have a couple old 22RF barrel a Marlin and a Springfield and a new Ruger barrel . So nothing to do yesterday I pulled some lead 22RF bullets . And I run the slugs down the barrels , and you talk about loose spots in a barrel . The Springfield the middle of the barrel I think the bullet could fall thru the bore but was pretty tight at the last inch at the muzzle , The marlin had some light spots in the barrel l but pretty tight , and the Ruger was snug most of the way really tight at the muzzle . Now I have to figure out how they tapper lap a barrel . Probably just do less strokes on the muzzel end .

 

[J_Hensley]

That's pretty interesting (and also disappointing)

I've never heard of such a procedure. Are you just pushing with a cleaning rod?

 

[ArtinNC]

That's pretty interesting (and also disappointing)

I've never heard of such a procedure. Are you just pushing with a cleaning rod?

I start the bullet with a nail set to get it started then use a old cleaning rod with the end cut off and polished . And push the bullet thru the barrel they have loose and tight spots all the way thru the barrel. Haven't done a high dollar barrel Just some old barrels .

 

[J_Hensley]

Most of my stuff hasn't been shot a lot, but I have an old Winchester pump gun I'm curious to check.

You have piqued my interest, one more thing to tinker with.

 

[dusterdave173]

A trick is to buy air rifle Slugs--they look like a bullet and are cupped in the rear--the cool part is you can buy them undersized in various sizes--why use a distorted pulled bullet? These make the job a breeze --You can feel most of what you need to know without having to Jam it so hard--I found an oiled patch first makes things easier--barrels will surprise you--my CZ barrels are tightest I have done--my old 40X the slug fell through it until the muzzle
Now how do you decide what is good or bad?? I do Not know--my 40 x was so big it scared me but it shoots damn good
Every barrel so far was tighter at the muzzle like I have heard they are supposed to be
Fun to do--what we learn? Above my pay grade

 

[ArtinNC]

A trick is to buy air rifle Slugs--they look like a bullet and are cupped in the rear--the cool part is you can buy them undersized in various sizes--why use a distorted pulled bullet? These make the job a breeze --You can feel most of what you need to know without having to Jam it so hard--I found an oiled patch first makes things easier--barrels will surprise you--my CZ barrels are tightest I have done--my old 40X the slug fell through it until the muzzle
Now how do you decide what is good or bad?? I do Not know--my 40 x was so big it scared me but it shoots damn good
Every barrel so far was tighter at the muzzle like I have heard they are supposed to be
Fun to do--what we learn? Above my pay grade

Come to think of it , think I have some , Some where have to look for them .

 

[PWNolan]

I've always cleaned and dried the barrel first for consistency and no added lube. The slugs should have enough lube

 

[TRSR8]

A trick is to buy air rifle Slugs--they look like a bullet and are cupped in the rear--the cool part is you can buy them undersized in various sizes--why use a distorted pulled bullet? These make the job a breeze --You can feel most of what you need to know without having to Jam it so hard--I found an oiled patch first makes things easier--barrels will surprise you--my CZ barrels are tightest I have done--my old 40X the slug fell through it until the muzzle
Now how do you decide what is good or bad?? I do Not know--my 40 x was so big it scared me but it shoots damn good
Every barrel so far was tighter at the muzzle like I have heard they are supposed to be
Fun to do--what we learn? Above my pay grade

You use an actual 22 slug Dave because other than feeling, measuring, the visual inspection of that slug is rather valuable. Also, done properly you distort nothing.

 

[houligan]

One other little trick to save time. I pick up a bag of bullet shaped lead sinkers for fishing with small plastic worms, at my local sporting goods store. They are cupped in the rear so a rod stays in the center all the way down the barrel. I can't remember the size number that I purchased but I think it may be the smallest one. Take a new 22LR round with you and you can come very close by eyeballing it! A bag or two will last longer than you'll need. I also picked up a piece of 3/16" coated steel rod at Home Depot, rounded the end to fit the cup on the sinker, and away we go! Since I'm retired, I just don't have enough to do in this cold weather.

 

[JohnnyJohnsoninWI]

You use an actual 22 slug Dave because other than feeling, measuring, the visual inspection of that slug is rather valuable. Also, done properly you distort nothing.

Please share your technique. I'm always up to learning a better method. A couple pictures would be great, too. Thanks.

 

[hoz53]

Been reading about slug barrels , So I have a couple old 22RF barrel a Marlin and a Springfield and a new Ruger barrel . So nothing to do yesterday I pulled some lead 22RF bullets . And I run the slugs down the barrels , and you talk about loose spots in a barrel . The Springfield the middle of the barrel I think the bullet could fall thru the bore but was pretty tight at the last inch at the muzzle , The marlin had some light spots in the barrel l but pretty tight , and the Ruger was snug most of the way really tight at the muzzle . Now I have to figure out how they tapper lap a barrel . Probably just do less strokes on the muzzel end .

Gordie has a section in one of his videos about slugging the bore. Also there was a thread here at AS about how to lap. you could prob find it if you searched. Ive only done CFs so far. also so far Ive used Neco slugs and brass rods but gonna have to check into that other stuff.

 

[Alex Wheeler]

I use a pulled slug as well. I will push that slug through a few times before using a new one. Sometimes that used slug can give a little more subtle feedback. Im not an expert but I did send 3 barrels to the test facility and grading by how they slugged, the results followed how I predicted they would shoot. In my limited rimfire experience I have been surprised at how differently barrels slug. Both the inconsistency and the consistency of different makes.

 

[ArtinNC]

I just did this on some old barrels that I had .J just to see if there was a difference in the bore , and there was quite a bite . What am I going to do with that info ? probably trash can it . Do it to a new barrel I drought it .

 

[TRSR8]

A further note, also regarding an actual slug, this pertaining only to taper lapped match grade barrels.
Lot’s understand the best barrels tend to be taper lapped but taper is one thing, consistent, progressive taper, quite another.
The best barrels tend to not have the same dimension for more than a couple inches ideally.
If you become adept at slugging you should systematically reverse that slug from the muzzle all along the barrel.That slug should loosen up immediately which tells you how progressive the taper is.

 

[Tad_Earhart]

Actually when reversing a slug in a bore that has a great, slow rate of taper that is consistent from one end to the other, the slug should slowly but progressively loosen up. If the slug loosens up quickly in a section say one or two inches long on reversing the slug, the rate of taper through that section is not very gradual.

There are a lot of barrels out there that show the pattern of: Section of straight bore, then short section of bore taper, then a section of straight bore, then section of short taper, etc. Ideally, it should have 1.5-2.5 tenths of consistent gradual taper from chamber to crown but it is very very few that get there. 2 tenths of bore dimension change is enough to go from a slug that the bore is in control of to a slug that you could probably blow dart out the end. Its actually pretty impressive how little of a change can be felt when done right. As far as lubed or dry slugs and bore, it is a personal preference. Many like to have everything lubricated when slugging it but I strongly prefer for both to be clean and dry. Just provides the feel I am looking for.

Tad

 

[dusterdave173]

So far after slugging a half dozen I can't seem to connect how they feel to actual results because every barrel has been so different--I have an old 40x that the slug almost falls through until the last few inches--it shoots amazing--my CZ 457 MTR is very snug and very even all the way down then very snug at the muzzle and it also is a winning rifle--I have yet to find one that has a loose spot or constriction mid barrel-
I am banking the experiences and tracking rifle performance --maybe one day I will start to understand what signs of trouble are --if that 40 x with a drain pipe for a barrel still shoots -I don't know--except is does constrict right at the muzzle.

 

[Bob3700]

Interested in rf bbl slugging? Check out Calfee’s book. He covers bbl slugging in great detail. His criteria for a bbl that “ shoots” may be very different ( rf benchrest) than what is being discussed here. I have a 40x and a 1913 that “shoot” but would not be competitive in a rf benchrest match. Slugging those bbls is interesting though.

 

[TRSR8]

So far after slugging a half dozen I can't seem to connect how they feel to actual results because every barrel has been so different--I have an old 40x that the slug almost falls through until the last few inches--it shoots amazing--my CZ 457 MTR is very snug and very even all the way down then very snug at the muzzle and it also is a winning rifle--I have yet to find one that has a loose spot or constriction mid barrel-
I am banking the experiences and tracking rifle performance --maybe one day I will start to understand what signs of trouble are --if that 40 x with a drain pipe for a barrel still shoots -I don't know--except is does constrict right at the muzzle.

Remember, all this primarily used in custom match barrels.
For most of the stuff you’ve quoted the single biggest task is probably to see if there are big loose spots especially near muzzle.

 

[dusterdave173]

Remember, all this primarily used in custom match barrels.
For most of the stuff you’ve quoted the single biggest task is probably to see if there are big loose spots especially near muzzle.

Appreciate the insight!

 

[wsmallwood]

Interested in rf bbl slugging? Check out Calfee’s book. He covers bbl slugging in great detail. His criteria for a bbl that “ shoots” may be very different ( rf benchrest) than what is being discussed here. I have a 40x and a 1913 that “shoot” but would not be competitive in a rf benchrest match. Slugging those bbls is interesting though.

Bill's criteria was essentially that the bore should be tight enough to maintain a seal with the bullet all the way through the barrel. He always slugged them and when I first met him almost always lapped them. In later years most would be lapped from the factory especially Muller and Shilen. After slugging and maybe lapping he would check the seal. He would run a slug maybe 8-10 inches down the barrel and then put anotther slug in and push it. If it was good the second one would push the first one out with some force. It would actually sound almost like a .22 report, of course it was in the confines of his shop. He sometimes had competitions to see who could do best on a target he put on his shop door using that method. So, while surprisingly loud, there was not a great deal of velocity. But it was proof of the concept.

I notice the OP said his Springfeild was inconsistent until the last inch or so. I'm curious as to how it shoots. A lot of high dollar factory guns use that method to make accuracy (precison) and it works fairly well. The unturned end of a lot of Anschutz rifles are just for that reason or at least used to be. They will not maintain that seal until the bullet hits the tight spot then a lot of them are almost as good as custom barrels. Turning that area down to match the rest of the barrel will cause the bore to "grow" and you lose that effect