Slugging a bore with 209 primer?

[2ndAmendmentNut]

I recently watched a youtube video with a guy explaining his method for slugging bores.

He takes a fired empty case, drills out the primer pocket to accept a 209 shotgun primer, presses a pure lead boolit into the case (no powder), then loads and fires the round into a box of rags.

This method sounds pretty slick, anyone else try it already?

[375RUGER]

I did 30WCF few days ago, but with regular primer and a grain of bullseye. this only tells you what the tightest spot in the barrel measures.

[2ndAmendmentNut]

I did 30WCF few days ago, but with regular primer and a grain of bullseye. this only tells you what the tightest spot in the barrel measures.

I'll be honest, I guess I have only ever measured the tightest spot in my barrel. To date I have simply driven a slug from one end to the other and measured the end results and sized my boolits .001 or more over groove diameter.


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[Ballistics in Scotland]

Yes, but if you drive a lubricated slug slowly through the bore with a cleaning rod, you will feel whether the bore has any loose or tight spots, or tightens (usually good) or loosens (bad) along its length.

Even if you feel the need to do it by primer power, there is no need to spoil a case for it. A rifle primer will do it too. There is some possibility that either kind will leave the slug lodged mid-way, but it should be easily knocked out with the rod.

[turtlezx]

So what if its loose in some spots ???
What can you do about that ??

[375RUGER]

An example of a tight spot would be where a barrel band for sling swivel is soldered on to the barrel. I can feel that with a cleaning rod. What can you do about it? I did about a dozen fire-lapping shots. Could still feel the tight spot. 23 years later, I haven't noticed it when cleaning lately, guess I finally wore it down.

[dverna]

So what if its loose in some spots ???
What can you do about that ??

The barrel can be hand lapped to open up the tight spot(s).

Don Verna

[2ndAmendmentNut]

In general I shoot the largest diameter boolit that will chamber. The bore diameter is nice and all but in the end if it doesn't chamber it doesn't shoot.


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[2ndAmendmentNut]

Even if you feel the need to do it by primer power, there is no need to spoil a case for it. A rifle primer will do it too. There is some possibility that either kind will leave the slug lodged mid-way, but it should be easily knocked out with the rod.

That's good to know! I won't waste time drilling out a case.


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[Ballistics in Scotland]

So what if its loose in some spots ???
What can you do about that ??

Wish it wasn't, and perhaps save yourself some time if you are hunting for the reason why a rifle is inaccurate. Not buy it, if you are testing a rifle with that in mind. Not that an isolated loose spot necessarily harms accuracy. Some rifles blithely ignore a slight ring-bulge, especially if it is well along the bore, where pressure is lower. A tight spot, probably from something like a hard-soldered barrel band, is more likely, and can indeed be removed by lapping.

It is non-isolated loosening of the bore over a considerable area that is most likely to harm accuracy, and impossible to rectify if it does. It will most often be found near the muzzle, caused by atmospheric corrosion and/or careless use of cleaning rod or pullthrough, and that is the very place where pressure has declined so much there is no chance of the bullet expanding to fit.

[rintinglen]

So what if its loose in some spots ???
What can you do about that ??

Typically it will not be loose in spots, you will find a bulge--which may not be visible externally--where a passing bullet at sometime has found a partial obstruction and battered it out of the way. You see this quite often in old target revolvers, where someone unknowingly shot a stuck boolit out of the bore.
There really is no good fix for something like this other than a new barrel. However, a bulged barrel need not mean much. I have seen a Smith and Wesson Model 10 6 inch that was visibly bulged still shoot pretty good groups.

[.22-10-45]

Slugging my 1898 Krag rifle I found bore looser from throat to about 16" ahead. Read where this was common with the early hot burning erosive smokeless powders..this is area of highest heat. Used the Neco fire-lapping kit..bore now has a uniform .310" dia..a very slight .0001" taper from about 10" to muzzle..I think the lead bullet wearing down at this point in bore did this. Anyway rifle went from a 1.5" grouper to under 1" groups at 100yds.

[MostlyLeverGuns]

I have found 'loose spots' when slugging and even with a very tight patch. I expect a loose spot at the rear sight dovetail of most rifles, barrel bands can cause 'tight spots. Some of the 'ball' powders can cause a difficult to clean tight spot in the throat. Bill Calfee, in The Art of Rimfire Accuracy (Amazon) discusses slugging barrels extensively to determine bore taper, uniformity, roundness and many other accuracy factors useful on all rifles.

[jaysouth]

I had to sort through the effects of an uncle that passed on. There were several cases of depends. I found that such a box would capture a soft slug over 2 grs. bullseye. After several year, the contents of the box was shredded shredded to the point that would no longer stop a bullet.

I put the box out with the garbage one day. A big storm came along and scattered depends "shrapnel" all over several neighbor's yards. I pretended to not notice, but they sure did.

[Walstr]

I did 30WCF few days ago, but with regular primer and a grain of bullseye. this only tells you what the tightest spot in the barrel measures.

That's about what I did for my last "shot" on the range with my 1895GS 45-70; 2gr Unique + normal 405gr LRN pill; went 2/3 down bbl, pushed it out at home. Could have done this in church, never made a sound!

[Walstr]

I had to sort through the effects of an uncle that passed on. There were several cases of depends. I found that such a box would capture a soft slug over 2 grs. bullseye. After several year, the contents of the box was shredded shredded to the point that would no longer stop a bullet.

I put the box out with the garbage one day. A big storm came along and scattered depends "shrapnel" all over several neighbor's yards. I pretended to not notice, but they sure did.

What gun were you testing, that the "slug" exited? Rifles are easy, but I tried it on a 45LC pistol & 3gr Trailboss got the slug half way into the bbl; had to smack it back into the case!