Flattop With Oversize Throats

[blue45colt]

I have an old Ruger flattop .357 that has oversized cylinder throats.
It originally had a throat size range of .3590"/.3615" diameter.
I have honed the throats to within .3610"/.3615".
I have ordered a .360" diameter bullet sizing/lub die for my Lyman lub/sizer.

I'm thinking that in addition to this, I probably need to have an oversized neck expander/flare to accomodate the larger bullets.
The standard expander die I have has a .3555" diameter with a flare size of .3600" which may not be sufficient to flare the case and allow a .360"+ diameter bullet to start without shaving.

Has anyone plowed this ground before, and if so what were your findings?

Thanks

[Dale53]

This answer is not QUITE on point, but close[smilie=1:.
For a number of years I shot BPCR Silhouette. I learned that Lee's expander die used a stem without threads (a "floating" expander). That made it quite easy to make them up in a custom size on a lathe without worrying about running threads. I don't have a lathe but had a friend make me several expanders for various rifle calibers in EXACTLY the size I wanted. They worked like a charm. I prefer the Lyman "M" die style of expander so I had mine made in that design (the "M" die doesn't simply "flare" but actually expands the mouth of the case a separate diameter so the bullet just enters the case mouth square and sits there until seated). A look at a Lyman expander will show you exactly what I am talking about.

You can do the same thing with the Lee pistol expander. If you use a Dillon reloader, you can easily make one in a custom size on a lathe (again, no threads needed).

Just a suggestion...

Dale53

[44man]

I have an old Ruger flattop .357 that has oversized cylinder throats.
It originally had a throat size range of .3590"/.3615" diameter.
I have honed the throats to within .3610"/.3615".
I have ordered a .360" diameter bullet sizing/lub die for my Lyman lub/sizer.

I'm thinking that in addition to this, I probably need to have an oversized neck expander/flare to accomodate the larger bullets.
The standard expander die I have has a .3555" diameter with a flare size of .3600" which may not be sufficient to flare the case and allow a .360"+ diameter bullet to start without shaving.

Has anyone plowed this ground before, and if so what were your findings?

Thanks
Where are you going to get a .360 boolit mold? You ordered a sizer but do you have a boolit large enough?
Keep the case tension and make the boolit hard enough to resist it being sized when seated. That is, if you get a boolit large enough.

[S.R.Custom]

Where are you going to get a .360 boolit mold?

With throats of .361"+, he's going to need .362" boolits. Theoretically, that's the ticket. But...

In and of itself, that'll be easy --Mountain Molds or lap out an RCBS unit-- but the tricky part is getting a cartridge to chamber stuffed with such a fat slug. (Not to mention his seating/crimp die.) If he's lucky, the chambers are oversized to match the throats...

[runfiverun]

some of the 38 s&w molds are that size.

[44man]

With throats of .361"+, he's going to need .362" boolits. Theoretically, that's the ticket. But...

In and of itself, that'll be easy --Mountain Molds or lap out an RCBS unit-- but the tricky part is getting a cartridge to chamber stuffed with such a fat slug. (Not to mention his seating/crimp die.) If he's lucky, the chambers are oversized to match the throats...
That's true, but what I was wondering about is what he has to go through a larger size die! If he has a regular mold that drops a .357" or 358" boolit, a larger die will not help.
He has his work cut out for him.

[shotman]

I may have missed something. He said he honed the cylinders OK but the barrel is what the boolit travels through. Is it .360 or smaller?

[44man]

I may have missed something. He said he honed the cylinders OK but the barrel is what the boolit travels through. Is it .360 or smaller?
Yes, much more information needed. :confused:

[blue45colt]

Thanks guys for the responses. Let's see if I can provide some additional information.

Dale 53

Actually what I have in the way of a neck expander is a Lyman M die with the listed diameters. I'm not familar with the Lee dies you mentioned but I'll take a look at their web site to see if that concept is something I could use.

44 Man, Shotman & Supermag

I have two or three moulds that drop bullets in the range of .360"/.362" diameters, a Lyman 358429, 358156 and a RCBS 150 CB.
They may not size 100% to .360", but I think they should be close enought to seal in the reworked throats.
The bore slugs out close to .357" diameter.
I haven't measured the chamber diameters yet.....I'll do that this PM.

Good point about the fit of an oversize round with the seating/crimping die....will just have to see if it will work.

Before I honed the throats, three of them were over .360" with the remainder in the range of .359/.360", so I was already having to deal with large sizes. I just figured that it would be easier to develop a load if this variable was minimized.

If this approach does not work, I have a Lyman Keith HB mould, can't remember the number, that should seal ok.

Thanks again for all of your input......you have raised some points that I need to address.

[44man]

OK, boolits large enough so lets try the easy way first. Try a .359", I bet they shoot good.

[Char-Gar]

My thoughts on the issue at hand.

1) Way to much is made of making the bullets and EXACT fit to the cylinder throats. If the alloy is soft enough, the bullet bases will upset .002 to fill the throat and provide a good gas seal. The bullets will al be the same size once they hit the barrel forcing cone and enter the barrel. A thou or two difference in cylinder throat size won't make enough difference the the practical accuracy of the pistol, to mess with. ACWW is soft enough to upset at stout 38 special and above pressures.

The ony time you need an exact fit, is with rock hard bullets that won't upset and who wants to shoot those anyway?

So, any bullet .358 to .359 should work just fine.

2) Most any expander will bell the cases enough to take a .360 bullet. No need to expand the rest of the case as a good tight fit won't hurt anything, but probably improve the burn. The round may look like the snake that ate the pig, but that will do no harm.

3. Folks spend to much time reading about guns in the pulp press and on the internet. They should spend more time shooting and let their firearms teach them. Most often they will find out the stuff they read doesn't square with real world shooting.

Gun writers write stuff to fill articles to sell and they are more concerned with appearing knowledgable than they are with the practical application of what they write. Others pick up the information and repeat it, and it gets repeated again until it becomes "holy writ".

4. Most shooters can't shoot a hangun well enough to tell the difference in what all of this tech stuff is about.

5. Your good old Ruger, probably didn't need any messing with but would have pleased you from the start if you didn't start worrying about stuff that doesn't need to be worried about.

[44man]

My thoughts on the issue at hand.

1) Way to much is made of making the bullets and EXACT fit to the cylinder throats. If the alloy is soft enough, the bullet bases will upset .002 to fill the throat and provide a good gas seal. The bullets will al be the same size once they hit the barrel forcing cone and enter the barrel. A thou or two difference in cylinder throat size won't make enough difference the the practical accuracy of the pistol, to mess with. ACWW is soft enough to upset at stout 38 special and above pressures.

The ony time you need an exact fit, is with rock hard bullets that won't upset and who wants to shoot those anyway?

So, any bullet .358 to .359 should work just fine.

2) Most any expander will bell the cases enough to take a .360 bullet. No need to expand the rest of the case as a good tight fit won't hurt anything, but probably improve the burn. The round may look like the snake that ate the pig, but that will do no harm.

3. Folks spend to much time reading about guns in the pulp press and on the internet. They should spend more time shooting and let their firearms teach them. Most often they will find out the stuff they read doesn't square with real world shooting.

Gun writers write stuff to fill articles to sell and they are more concerned with appearing knowledgable than they are with the practical application of what they write. Others pick up the information and repeat it, and it gets repeated again until it becomes "holy writ".

4. Most shooters can't shoot a hangun well enough to tell the difference in what all of this tech stuff is about.

5. Your good old Ruger, probably didn't need any messing with but would have pleased you from the start if you didn't start worrying about stuff that doesn't need to be worried about.
HOOOORAY, common sense at last.
Except I do use hard boolits and a few thousandths does not mean a thing.

[targetshootr]

4. Most shooters can't shoot a hangun well enough to tell the difference in what all of this tech stuff is about.

That's why I think a person is better off shooting offhand, it gives real world results. Without a Ransom rest, shooting off bags is almost the same as offhand.

[blue45colt]

Thanks again to each of you who has responded. You provided a lot of good useful input.

I indeed plan to start load development with bullets sized "normal", ie: .358" diameter using air cooled WW alloy and see where that takes me... .358" is the largest size die I have at the present.

I don't think I caused any harm by honing the throats to all be closer to the same size. To my way of thinking that just minimized one variable in the process.

[Char-Gar]

No..you didn't do anything harmful...just uncessary. Those bullets will all be the same diameter after they have traveled their length down the barrel.

[nicholst55]

I have an M25-5 Smith in .45 Colt, with throats running from .456-.457". Using common wisdom, I need boolits that are at least .458" in diameter. It seems, however, that nobody told the gun that. It shoots .454" boolits just fine - as well as I can hold with bad shoulders and 53 year-old eyes, anyway.

The moral of my story? Try it with what you've got - you might be surprised how well it does.

[Bass Ackward]

Well not to be the fly in the ointment here, I think he done right.

If throats are a different size, then more or less pressure escapes before seal each time. This means a different pressure curve.

That means more or less lube on bullets.

That means a different approach speed to the forcing cone.

That means more or less lead left behind in the forcing cone unless the BC gap is wide enough to let it out. And just what part of the slug does that lead come from?

Since there is a lot of slop in a revolver notch for most revolver brands, a bullet is going to do what has to be done to get out of there and will eventually wear away improperly placed metal. But a bore gets 5 or more (depending on how many) shots to clean up than a cylinder throat does. So that takes the longest to break in on anything if it is actually causing fliers.

Doesn't mean that you can't make something work. Just like people, there is some load out there for every gun. But I want one that isn't picky.

So for me, uniform size is important regardless and quite honestly has been more of a problem to purchase than "perfect" size or alignment on the last 10 guns purchased. But after all IS said and done, Professor Gun is the only expert.

[Char-Gar]

Bass.. About 25 years ago I started measuring the cylinder throats of every sixgun I could get my hands on. I now have a short database of about 150 sixguns made by Smith and Wesson, Colt and Ruger. These handguns are in 38/357, 41 Magnum, 44 spl and 44 magnum, 45 AR and 45 Colt. They cover a hundred years production span.

I have yet to find a sixgun with all six cylinder throats the same. Some have a variance of as little .0002 and others as large a variance as .0008. Yes, it takes some pretty sophisticated instruments to measure this close, but L.S. Starrett makes such.

I have reamed a few cylinders with a new high high quality reamers and come darn close to every cylinder the same. The difference was so small, I could not repeat the measurements and if not repeatable, they they don't count.

I have fired several hundred thousand rounds through several score sixguns, and could never find any accuracy difference that could be traced to normal cylinder throat variation.

I gave all of this testing and theory up several years back as I learned that most of it was like trying to find the end of the rainbow. It could be fun for a time, but after you have done it and done it, you found out it really didn't matter enough to continue the chase.

There are some sixguns that just won't shoot no matter what you do and some who will shoot very well regardless of what you do. The rest fall in the middle of just being average. As long as the cylinder throats are as large or larger than the barrel groove diameter, you can shift your focus elsewhere. If those throats are smaller than barrel groove diamter, it is time to reach for a reamer.

Most of this picky little stuff that makes up bulk of conversation about sixgun accuracy on the web is like arguing about how many angels can dance on the head of a pin.

Most folks would be better served by shooting and let their guns teach them, than following the gurus like sheep. There is so much unvarnished horse manure floating around that folks believe and repeat until it is accepted as holy writ. Trace it all back to the source and you will fine somebody was trying to make a buck on the deal.

The original folks on this site have exploded many "old wives tales" and myths about cast bullet shooting and there is work yet to be done.

As this site grows, we find those same "old wives tales" and myths comming back to life. They seem to be like Jason in the Friday the 13th Movies.

Bass, I am not including you in the above, for I know you are a man of much practical experience and extensive knowledge. I am just spending a little time reflecting on the issue at hand.

[felix]

Yeah, Charles, I was convinced as you when I sent a 22LR/22Mag Ruger back to have its firing pin replaced. The gun came back with the lawyer trigger and transfer bar. Did not shoot the sucker for a year because I was mad. But when I eventually did, the gun was 10 times more accurate it seemed. Therefore, lockup and its placement has EVERYTHING to do with accuracy in a revolter. ... felix

[Char-Gar]

Yes indeed...proper lockup and timing is critical to sixgun accuracy. If you have a charge hole ever so slightly misaligned with the bore, you will never get extreme accuracy out of that sixgun. That is the theory behind line boring a cylinder, but many sixguns come from the factory with good timing and alignment. Those are among those sixguns who will shoot regardless of other features that are not perfect.

If you have a well timed and aligned sixgun, it will shoot like a house-a-fire even if it does have those little pesky variances in cylinder throat diameter.

Some folks like to recut the forcing cone, thinking that will take care of minor misalignment problems. Make the cone bigger and the bullet will skid and center itself in the bore..yea right!

In this regard, sixguns and rifles are much alike. One of the keys to primo accuracy it to introduce the bullet into the rifling straight, straight, straight.

I have a OM Ruger SS that I fited with a mag cylinder I bought on Ebay. It took a little stoning to get a fit, but it locked up tighter than a bank safe, and the charges holes are properly aligned. That little popper will shoot almost like a rifle. I did set the trigger about 1/2 pound below sanity.

[NHlever]

I just picked up an older three screw Blackhawk in .357. The cyilinder has too much end shake, and play in general and the chamber throats are on the large side (.359, or plus a bit). In a static state, everything seems to line up pretty well, and I have cast boolits sized to fit the throats, but the gun doesn't shoot well at all. On the bright side, it doesn't lead either. :D When the gun is fired, that cylinder slams around using up all the play there is, and I doubt that two boolits in a row hit the forcing cone the same way. I'm not sure if it will become a .44 Special, or if it will just get traded for something different. If I still had good access to machines I would bore out the hub on the cylinder, and press in a hardened bushing, and re-establish headspace, and barrel / cylinder gap. Alignment, and lack of slop are everything for sure.

[MT Gianni]

Some great points are stated here. The biggest problem IMO, is when throats are smaller than the bore. Sizing down then expanding with a bbl/cylinder gap is trouble if it does happen. Throats too big are best shot to establish a base point. Let us know how things evlove with it. Gianni.

[Bass Ackward]

I have fired several hundred thousand rounds through several score sixguns, and could never find any accuracy difference that could be traced to normal cylinder throat variation.


Sorry, just getting back.

I wish you could have seen what I have been dealing with. I had a Redhawk that would group 4 shots in 1/2" and to chambers that were directly opposite each other that would throw every load, every time, out at least 2" in opposite direction opening the group to a 4"er at 25 yards. Always 10 o'clock and 4 o'clock. Powder, powder charge made no difference. By that I mean that the cluster would open or close, but the fliers were always right there in EXACTLY the same spot. Got so I could win money by taking a magic marker and putting the dots on the targets where the bullets would hit.

I "thought" the problem was misalignment. I figured that I would shoot the gun until I got an indication from the forcing cone which way they were off. Fulled me, perfectly cylindrical tool marks in the cone indicating perfect alignment. That's what I get for spot checking throats. The throats were .4325 roughly. So I sized .432.

The problem children I missed were .431. Once corrected, the gun no longer exhibits this pattern and is accuractye with almost anything you want to put through it.

And if you want something to really blow your mind, I am doing a before and after on two new S&W 44 Mags that both had .428 throats with .429 bores. So far, the undersized throats are winning handily over the guns today that are reamed to .4305 now. I think I know why, but I still have a few loads to finish.

[sixshot]

Chargar, did I read that correctly, you said several hundred thousand rounds, thats one heck of a lot of shooting, not doubting you just inquiring how you went about doing that. My best 2 years in competition were 86 thousand rounds total & I thought that was a lot.
Were you competing or just testing? Thanks in advance, Dick

[45 2.1]

Chargar, did I read that correctly, you said several hundred thousand rounds, thats one heck of a lot of shooting, not doubting you just inquiring how you went about doing that. My best 2 years in competition were 86 thousand rounds total & I thought that was a lot.
Were you competing or just testing? Thanks in advance, Dick

You should be able to just about wear out one good revolver with that much shooting. Shoot Bullseye, winter pistol league and combat matches for about 15 years and you'll rack up a lot more than that.

[sixshot]

More than SEVERAL HUNDRED THOUSAND! You guys are amazing & I mean that sincerely! I've heard of people doing it but to me, several hundred thousand means 4-5 hundred thousand rounds, when you crunch those numbers over a 15 year period.........well its just real impressive. Over 2,000 rounds a month for somewhere around 15 years straight, & thats on the low side.

Good for you & anybody else with that kind of shooting under their belt.

Dick

[blue45colt]

Back with a little update.....

Time for testing has been in short supply the past few days.
Did load a few rounds with the Keith 173 gr. SWC sized to .358" and 11gr. 2400 powder. These shot ok....no problem with leading.....have not shot for accuracy yet.....still playing around with the powder charge. Once I settle on a charge, I will spend some time checking the accuracy.

The chambers are on the small side.....around .379". A round loaded with a .360" sized bullet will not chamber. It did however, chamber in my SP101 and Marlin 1894 with ease.
Anyone know what the size range (tolerance) is for .38/.357 chambers?

[blue45colt]

Back with a little update.....

Time for testing has been in short supply the past few days.
Did load a few rounds with the Keith 173 gr. SWC sized to .358" and 11gr. 2400 powder. These shot ok....no problem with leading.....have not shot for accuracy yet.....still playing around with the powder charge. Once I settle on a charge, I will spend some time checking the accuracy.

The chambers are on the small side.....around .379". A round loaded with a .360" sized bullet will not chamber. It did however, chamber in my SP101 and Marlin 1894 with ease.
Anyone know what the size range (tolerance) is for .38/.357 chambers?

[McLintock]

Excessive end shake was brought by NHlever, and he listed a way to fix it. For a cheaper way and for people that don't have accesss to the machine shop, the Brownell's Gas Ring Stretcher works pretty good. I've done a couple of my Ruger 3 screws with one and several guys over on the Rugerforum have them and report good results. It swages the existing bushing down and thereby lenghtens it to take up the slack.
McLintock

[NHlever]

Interesting. I have used those on Security Six's but I guess I thought the front hub on a Blackhawk was too thick for them to work. Those were initially designed inside the Ruger plant for armourer's use. I'll have to take a look at that. To be honest, I bushed them for customer service when I worked at Ruger, but never thought to try the swaging tool.