Insights Needed After Slugging Bbl & Gauging Throats

[alamogunr]

I've been following the 75000 Wadcutters thread since the beginning. Always meant to follow up with a similar, though less ambitious program. Now I'm finally trying to get started although at my age I doubt that I will put up those kind of numbers.

My questions center around the results I got from slugging the barrel of my S&W Model 28, Highway Patrolman. The first thing I did was to us my plug gauges to measure the cylinder throats.

All 6 throats accept the .357 gauge. One is just a tad tighter but with a little adjustment to the entry angle, it would go in and go full chamber.

I then slugged the bore. There was more resistance where the barrel threaded into the frame. The slug measured .3529. I was able to calculate that measurement using a Vee block I obtained from a member here. The calculated groove diameter is .3529".

To double check this, I used the .357 plug gauge in the Vee block and calculated a diameter of .3574(for the gauge only). I figure that is close enough.

At this point, I don't think I need to do anything. If anything is required, I could fire lap the barrel to remove what seems to be thread crush where the barrel threads into the frame.

I guess I would like to hear what members with more experience in this area think my next move should be.

[slughammer]

Take your slug and drop it through your .357 dia throats to verify that .3529 dia. It should rattle as it passes through. (I wouldn't trust that .3529 measurement)

Also, feel free to take the same slug and push it through your barrel 2x. It should pass relatively easy through most of the bore, you'll feel thread choke when you get to it.

[Outpost75]

Might also want to be sure chambers and barrel are clean. The early magnum ammo leaded heavily and you cold still have deposits.

[ShooterAZ]

I don't really think you need to do much of anything IMHO. I think your next move would be casting up a bunch of 148 gr wadcutters, size them to .358, and lube them with thinned LLA. Load em' up and shoot em'... Then report back.

[alamogunr]

Take your slug and drop it through your .357 dia throats to verify that .3529 dia. It should rattle as it passes through. (I wouldn't trust that .3529 measurement)

Also, feel free to take the same slug and push it through your barrel 2x. It should pass relatively easy through most of the bore, you'll feel thread choke when you get to it.

That is why I asked the question. The measurement seemed too small to be thread choke. I measured the slug several times, both with the Vee block and by wrapping the slug w/a .0015" feeler gauge. Both measurements came out within a few tenths. I do know how to read a mic.



Might also want to be sure chambers and barrel are clean. The early magnum ammo leaded heavily and you cold still have deposits.

I ran a tight patch thru the barrel and a similar patch thru the chamber throats. It looked clean but I suppose I could do the Chore Boy thing to the barrel. This gun has been shot very little.

One thing I would like to do before I go to the extreme of fire lapping is partially slug the barrel. To do that I need several short lengths of brass rod small enough to fit the breech and stack them until I can drive the slug back out the muzzle. I've got lots of brass rod but all if it is too large to fit the barrel.

[alamogunr]

I don't really think you need to do much of anything IMHO. I think your next move would be casting up a bunch of 148 gr wadcutters, size them to .358, and lube them with thinned LLA. Load em' up and shoot em'... Then report back.

I wish I had read your post before I went back and slugged the barrel again. I've got a bunch of 148 gr wadcutters(H&G #50) already lubed with a variation of LLA. I know I need to shoot but with a 70 mile round trip and raining to boot, I couldn't get in the mood.

[slughammer]

How does your slug fit the throats?

Have you tried pushing it through the barrel a second time? You can really feel thread choke that way.

[tazman]

Talking about small groove diameter revolvers, I have a S&W model 60 3 inch in 38 special. The throats measure .356. The groove diameter is .354 and a tiny bit.
I have never sized boolits smaller just for this gun. I shoot the same .357-.358 boolits I shoot in all my other 38 special/357 mag revolvers. It shoots those "oversize" boolits extremely well.
I doesn't lead any with the larger boolits either.
Try your loads in your gun and see how it shoots before you make any decisions about doing any work on the gun.
Things don't need to be perfect in order for the gun to shoot well. They just need to be like a funnel going from the chamber to the front of the barrel. Throats larger than the groove diameter of the barrel.
Yours seems to fit that description.

[DougGuy]

A soft enough boolit, with magnum levels of pressure will very often pass through a choke and then obturate to fill the bore. This is what j words do when they shoot good through a known thread choke because they have a soft lead core swaged into the jacket.

Push a soft lead ball through the bore and then see how it fits in the throats. It should go through the throats easily. If you then push this same ball back into the bore, and it fits loosely, I would consider firelapping. If it goes through the bore then fits relatively snug the second time, you don't have much choke and I likely would just shoot the gun if it was mine and not worry about it.

[alamogunr]

Per post #2, I dropped the slug thru the throats. As I said, it just dropped thru without hesitation. Tomorrow I will slug the barrel a third time and then follow DougGuy's suggestion and if it drops thru the cylinder throats, push it thru the barrel again and feel for restriction.

The slugs I'm using are barrel shaped lead fishing weights. In the past, I've always tried to keep the slugs I used on rifles. I'm going to keep at least one that I used on this pistol. Regardless of the results, I'm going to shoot it with .357 wad cutters when it stops raining and see how it works. I'll get some loaded up this weekend. I don't shoot weekends. Range too crowded and I'm kind of a loner anyway.

tazman, If the groove diameter was within .002" of the throat, I would forget all this. I'm finding .004" difference. I'm not sure obturation can make up that kind of difference. That difference is why I posted the OP. I wanted someone to tell me if that was normal for thread crush. Shooting should prove one way or the other.

I'll return next week.

[tazman]

Unless I am misreading your first post, all the throats are larger than your bore. Anything that goes through the throats with a snug fit should get squeezed down by the barrel. That isn't a problem. It may be a smaller bore than most but still not a problem.

[alamogunr]

tazman, You are correct. The throats are larger than the bore, especially the area where the barrel threads into the frame. This pistol is in very good condition, the chambers are recessed for the rims and the barrel is pinned. It is one of two I picked up several years ago. I sent what I thought was the lessor of the two as far as condition to Jim Stroh, since retired. He converted that one to a .44 Spec.

I am satisfied with the throats. They are all as consistent as I have ever seen and , thank goodness, larger than the bore. Given some decent weather, I'm going to shoot next week. I don't want to depend on obturation since I want to shoot light loads and lots of them.

I do remember a quote(sort of) by Veral Smith in his book. "When the big light hits the bullet, it will fit".

[tazman]

Now all we need to see is what you get when you shoot it.
Enjoy.

[9.3X62AL]

I think all will be well once the weather allows for some range time.

[dubber123]

The throats larger than the bore is a great start. If it has thread choke, it needs to go in my opinion. I've never seen a barrel with a thread choke as being a positive thing, and it's easy to get rid of. Enjoy your new project :)

[alamogunr]

Just in case I think I need to do something about thread choke, I spent about an hour casting up some soft lead boolits. If shooting indicates that I need to lap, I plan to load about 20-25 rounds. I looked at my molds and the De Carli wadcutter seems to have the most drive band area(carry more lap compound), so that is what I cast. Didn't pre-heat the mold because I figured that a few wrinkles wouldn't hurt anything.

[skeettx]

HOW does she shoot??
Lots of measurements and no data yet :)
Click, bang, data
Mike

[alamogunr]

Easy there! No more measurements until I get to shoot. I've got to load up some H&G #50's and then find a day when I don't have something hanging over my head and can make that 70 mile round trip to the range. Today was the first day w/o rain in several.

Plus, I want to load some lapping rounds just in case. The boolits that I cast today have to be sized. They came out .360 and I don't want to lap my throats.

I'm spending today preparing my Sunday school lesson for tomorrow. That takes a lot longer now than it did 15 years ago.

[dubber123]

If you decide to lap, the wadcutters will work well. I use them for all my 35 cal fire lapping loads.

[44MAG#1]

Are you always going to shoot from the bench or are you going to shoot offhand? There is a difference in the type shooting making a difference in what you need, right?

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

[fourarmed]

Clean the bore and find the largest of your pin gauges that will enter the muzzle. Let it slide down the barrel. You will soon know if you have choke. If you do, go to smaller gauges until you get one that will go all the way through. Then you will know how much.

[DougGuy]

My favorite but highly un-scientific way to check thread choke involves patching a plastic cleaning jag very tightly into a clean bore, and observing how much effort it takes to keep the jag moving at a constant rate down the bore. Any change in resistance, directly correlates to a change in bore diameter. It is very effective in that it lets you "feel" exactly what the boolit will be subjected to when it travels in the bore.

After using this method on considerable handguns, a few things are quite apparent. First off, the old Ruger 44s with the circle on the barrel, are very prone to having a "bulged" area just in front of the frame, where the jag will become totally loose in the bore for about 3/8" of an inch then it will snug back up again when it enters the threaded shank portion that is threaded into the frame. Very common with these older SBHs, it comes from how Ruger faced, fit, and torqued the barrel into the frame.

Another anomaly comes from the "Lawyer Warning" that is rollmarked extremely deep in the outside of the barrel, you will see raised ridges inside the rifling behind the lines of text on the outside. Yep, that's how hard they impressed the rollmark into the barrel, so much that it created distortions inside the barrel. With a cleaning jag, pushing it rapidly past these ridges will feel like the rumble strips used on our roadways to caution drivers to slow down.

Thread choke that is minimal, can barely be felt by the jag, resistance against motion will only increase slightly. Choke that is severe will stop the jag and require beating the cleaning rod with a hammer to drive it through. These should be sent back to Ruger, as no amount of firelapping will remove a choke this bad without ruining the rest of the rifling in the barrel by the time the choke is gone.

This could be measured with pin gages, choke that is barely noticeable is less than .001" moderately noticeable is .001" to .002" severe chokes are .003" or more constricted.

It will require about 6x the effort to lap a stainless Ruger barrel as it will to lap a blued steel barrel.

Placing a white piece of paper on the recoil shield and shining a bright light on the paper, looking down the bore you can see thread choke with the naked eye. It looks like a hazy distorted "ring" about 5/8" to 3/4" from the bottom of the bore. If you can't see it, you likely won't feel any or very little change in the jag either. Barrels that will stop or noticeably slow the movement of the jag are very easy to spot the distortion with the naked eye.

[44MAG#1]

Has the OP even shot the gun yet? Why get "out of sorts" until he has shot the gun to see if he needs to do anything. Keep It Super Simple should apply here. Until he finds out that it is not super simple.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

[9.3X62AL]

Has the OP even shot the gun yet? Why get "out of sorts" until he has shot the gun to see if he needs to do anything. Keep It Super Simple should apply here. Until he finds out that it is not super simple.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

Hear, hear!

For a time I owned one of those Infamous Ruger Blackhawks In 45 Colt, my much-celebrated Built Backwards Bisley that came with .452" grooves and .448"-.449" throats. I did correct that anomaly in due time, but it is also germane to the story that one bullet design actually shot REALLY WELL in that amalgamation of dimensional nonsense--the Lyman #454490. Fact is--that bullet shot SO WELL, from 800 to 1200 FPS, that I palavered around for close to 3 years debating whether I should hone the throats or leave well enough alone. I decided to sally forth, and the outcome is a good one--now the revolver shoots castings of all sorts with good to excellent accuracy, including #454490.

Moral of the story--sometimes The Conventional Wisdom is neither "conventional", nor is it "wisdom". Let the gun tell you what likes, hates, and doesn't give a darn about. That will require shooting (aw, shucks!) :-)

[44MAG#1]

I think its funny really. People buy a new handgun and before they even fire it they are running in a circle wringing their hands worrying about what they need to do to it to get it to shoot well.
Shoot the gun some to see if it needs anything done to it. It may and then it may not. But how will someone know if they dont shoot it.
Funny just funny to me.


Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

[DougGuy]

What's even funnier, quizzical to me even, is that for instance, the throats are tight, people say shoot the gun. Okay, the gun will shoot. you can even put a 44 cylinder in a 45 and shoot it, this will work! BUT....

Shooting the gun is not going to magically enlarge the throats, and I think by now we ALL know that the proper relationship between the throats and the boolit will let the gun perform to it's best, so it's a no brainer that you can shoot it and see how good it shoots, and then see an improvement AFTER the throats are corrected and the gun shoots better groups. Some of us would rather tweak the gun first knowing that it is not as dimensionally good as it can be, and it will not shoot its best until it is.

[44MAG#1]

What's even funnier, quizzical to me even, is that for instance, the throats are tight, people say shoot the gun. Okay, the gun will shoot. you can even put a 44 cylinder in a 45 and shoot it, this will work! BUT....

Shooting the gun is not going to magically enlarge the throats, and I think by now we ALL know that the proper relationship between the throats and the boolit will let the gun perform to it's best, so it's a no brainer that you can shoot it and see how good it shoots, and then see an improvement AFTER the throats are corrected and the gun shoots better groups. Some of us would rather tweak the gun first knowing that it is not as dimensionally good as it can be, and it will not shoot its best until it is.

Not going to argue this subject. How simple is it to go to the range and test a few loads and see how the gun shoots? Other than the cost of the ammo and fuel going to the range the cost is very little.
How many people can tell the difference between a load that groups 1 inch groups off the sandbagged benchrest and a 2 inch load off a sandbagged rest at twenty five yards when shooting from field shooting positions out to one hundred yards including offhand shooting. Now, I am not talking about someone that drags some form of a portable benchrest out to the field or woods or something of that nature. From observation i can tell you very few are capable of it. It is nice to dream but dreaming doesnt negate reality. Reality is an ugly thing but it is something that is there and will always be there.
Each one do as they want as I surely will. But I am firmly grounded in reality.

Again I mean no hurt, harm, anguish or turmoil by my post I have posted on this posted subject. I am not baiting, trolling or calling out anyone. I am making a post based on my experience, knowledge and/or belief or opinion. That is all.

[alamogunr]

Clean the bore and find the largest of your pin gauges that will enter the muzzle. Let it slide down the barrel. You will soon know if you have choke. If you do, go to smaller gauges until you get one that will go all the way through. Then you will know how much.

Well! I finally found time to do as fourarmed suggested. I got out the plug gauges and tried several until I found the one that fit very well in the muzzle. Although I oiled it well, I had to nudge it down the barrel. It didn't take any pressure, it just wouldn't slide by inverting the gun. Much to my surprise the gauge slid all the way out the breech. There was no play at either end of the barrel. I had to invert it muzzle down to remove the gauge since the gauge was too long to clear the breech.

I have no idea why I felt more resistance when I slugged the barrel unless by the time it got to the area that is threaded into the frame it ran out of oil and was trying to go thru dry. I didn't notice any smears but then I wasn't looking for any either.

I appreciate the patience all have shown in this thread and hopefully I will find time to go shoot before Christmas. I'm going to load wadcutters in .357 brass for now to keep the boolit well into the throat. Probably not necessary but I've go some new Starline .357 brass that I've been wanting to load anyway.

[tazman]

That sounds like you ran a good test. Appears there is no choke in the barrel. Now just go out and shoot it.

[toallmy]

Enjoy shooting with the added confidence in knowing all is well .