S&W Mod 29 throats

[bushytail man]

I just received my Grizzly 9794 pin guages. These are minus gauges (.0002). I measured my cylinder throats on my Mod. 29-2. The .431 was the largest pin to go all the way through. The .432 stopped half way through the cylinder.
What is the diameter of my cylinders? What do I do next to check?
What size boollt is needed for this gun?

.429 jacketed Remingtons shoot excellent in this gun, but I want to shoot cast too. Thanks.

[dubber123]

I'd size .431" Being minus pins, .431" should be a snug fit. I wish the throats on my older 629 were that tight. Mine are .433"ish. The newer 629 is much better.

[Mal Paso]

I'd size .431" Being minus pins, .431" should be a snug fit. I wish the throats on my older 629 were that tight. Mine are .433"ish. The newer 629 is much better.

My buddy has .428 Throats on his 629 with a .429 groove and mine used to before I reamed them. I agree tighter is better but only because you can remove metal easier than putting it back.[smilie=l:

+1 on .431

Aren't those pin gauges cool?

[2 dogs]

To answer your question, your cylinders are tapered. They are .432" in the rear and .431" in the front. I would check to see if a .432" bullet would chamber. I suspect it will. Be sure to measure your bullets with a micrometer not a caliper. Oh yeah, while we are having fun, some of my guns shoot a .4315" bullet! The basic rule of thumb is to shoot the largest cast bullet that will fit in your cylinder throat.

[Char-Gar]

2 dogs be right!

[bushytail man]

If the cylinders are tapered, and measure .432 in the rear and 431 in the throats, how can a .432 bullet fit in the throats? The .432 gauge will not enter the throats and they are minus gauges so subtract .0002 from the .432 pin.
A .430 bullet fits into the throats and stops before exit, must be pushed thru. Any advice appreciated. Don't know anything about tapered cylinders or how to size for them.

[Char-Gar]

A bullet does enter all the way into the throat when a round is chambered. There is a chamfer or lead at the back of the throat that guides the bullet into the throat. In the case above, a round with a .432 (or even larger) will easily chamber. When fired the bullet will pass through the .432 section of the throat and be squeezed down to .431 as it exits and enters the barrel at .431.

[LAH]

bushytail man I don't consider myself an expert on this but if a .430 bullet stops in the throats & won't fall through but can be pushed through without a bunch of effort...........that's what "I" would use. I set my Rugers up like this & they shoot fine & don't lead unless the barrel is choked at the barrel/frame junction.

With that said a machinest once told me, a 1/2 inch plug won't fit in a 1/2 inch hole unless you do something like heat/cold. Like I said, I'm no expert so if a throat was a true .432 a boolit .431 or only slightly larger should work.............I think.

[gray wolf]

Have I got this right ?? ( please )
As long as a loaded round will go into the chamber and is not a tite fit it's safe to fire.
So from that I get this.
If my throats are .432 -- am I to understand that a lead bullet can be bigger as long as the round will chamber and the nose does not hang up in the cylinder throat. Nose being the exposed part of the bullet.
So how the heck much is to big ? when is it unsafe to fire ?
My throats are .432 but I can load and chamber a .434 bullet. Whats it going to do in a .429 bore ?
All this in making me a little nuts.
I shoot .430 -- .431 -- and .432 with no leading, so what's a guy looking for ?
Is it an accuracy thing ? a leading thing ? or a safety thing ?
I read and read and walk away with no definitive answer.
If it's me, then tell me, If it can be explained, then explain it.
I can't get my head around answers that say--just go shoot it.
Snug fit ? push through with a pencil ? Loose fit ? as long as it loads in the cylinder ?
If you were building a custom pistol how would you set it up ?
I need a standard to go with, At least with that we know how far off the mark we are.
excuse me for this type of question, perhaps I get a little frustrated.

[Char-Gar]

Grey Wolf..

Your questions can be answered from a couple of different angles.

1. "Unsafe to fire".. Shooting a .434 bullet, through a .432 throat into a .429 bullet is not unsafe, unless the pressure of the load was at or near the redline to begin with. Sizing the bullets down in the gun will up the pressure, but not near enough to get into the red zone.

2. Because it is safe, does not automaticaly mean it will be accurate. That depends on a number of other issues.

3. I have the same question my self about what the OP is looking for. He seems to be getting good accuracy, but is troubled with the lead left in the barrel. Lead in the barrel becomes an issue if it causes accuracy to be degraded. All plain base gas check bullet will lead some bullet lube and lead wash in the barrel, that clean out without much effort. I am wondering what the fellow expects. Perhaps it is his expectations that need to be looked at.

Sucess or failure, contentment or unhappyness most often depends on our expectations. If our expectations are not reality based we will never be content or sucessful.

4. If I were building a custom sixgun, I would want the cylinder throats to be .001 over barrel groove and size my bullets to fit the throats. Some folks would want the throats and barrel groove to be exactly the same. The problem with that is outside of pure luck, there will be some difference due to barrel making and throat reaming tools. Nothing is either prefectly round or perfect in any other way. I want .001 "slip and slide" so I will know the bullet are entering the barrel groove diameter or a hair over.

5. I don't have custom sixgun, so I do like everybody else. I try and fit the bullets to the cylinder throats, but if they are .001 over or under, I don't worry about it.

6. I don't worry about snug fit, push through, loose fit or any of that. I clean the cylinder throats and measure them with a Starret hole guage and measure that with a Starret micrometer. This is the measurment I use. Trying shove a bullet, which is seldom, if ever round through a hole which is seldom, if ever round, does not seem very precise to me. I have been using the Starret guages for such things since 1968, so I am comfortable with their use and have not seen a need to buy pin guages.

7. I can understand your frustration, as answers to this type of questions, on this board, often seem inconsistant and sometimes contradictory.

8. I am one of those that often tell folks to "just go shoot it" because I see people fretting over problems and issues they read about. These issues may or may not be valid. Even if valid, my not have any effect in a real gun. So, instread of reading and fretting, just go shoot the darn thing. Quite often the supposed issues will go away with the powder smoke and prove not to be an issue after all. If, it is an issue, then and only then, is it time to look for answers and ways to fix the problem. Too many folks want to remove any possibility of less than perfect results, BEFORE they pull the trigger. This shot circuits the learning process. Most of us learn far more from out mistakes then we do our sucesses.

9. If you are content with what you are doing with your sixguns, then don't get unhappy because somebody else thinks you should be. Keep on shootin and grinin!

Different folks hold different opinions and do things different ways, but the above is how I respond to your concerns and questions.

[gray wolf]

Ask and you will receive
Very well put and I M H O a great answer.
Sometimes if your going to chase every rabbit in the field you may never get to fire a shot.
I used to do wood working and I measured a lot of things with a caliper.
I met a very good craftsmen one day and he laughed his A$$ off.
He said Son ! there ain't no piece of wood that's straight, and no saw blade that cuts a 100 % Get rid of those calipers and get you a ruler.
--- I got a ruler ---
Thanks again for taking the time to answer so nicely.


Sam

[bushytail man]

Char-Gar, what model Starrett hole quage are you using? Do you find that more accurate than pin gauges?
If it wasn't so much trouble, I would take the cylinder off and slug it.

[Char-Gar]

I use Starrett expanding hold gage (829). I expand the gauge and set it on top of the charge hole and make it smaller until it slips in. It should be able to slide up and down in the throat with a slight drag feel. If there is no drag I expand it until there is I then remove it and measure with a good mic that reads .0001. With practice I can get accurate readings plus or minus .0001.

The gauge can also be inserted fron the chamber end if you want to know if there is a taper. All of the precision tools require a little practice to get the feel. It not very hard.

[ClemY]

I have had to ream, in addition to the usual .45 Colt Ruger NMBHs, a S&W 629 Mtn gun and a DW 744. The amazing thing to me about the DW was that it seemed quite accurate with the 8” heavy barrel. When I switched to a 6” light barrel it wasn’t nearly as accurate with the same loads. After I finally acquired a set of pin gages I found the answer: the throats were all tight, but they alternated in two sizes: too small and really too small. I reamed it to .431” and it is now the most accurate .44 I have. I now also have a digital inside mic and the throats seem to measure about .4318”

[Char-Gar]

I have had to ream, in addition to the usual .45 Colt Ruger NMBHs, a S&W 629 Mtn gun and a DW 744. The amazing thing to me about the DW was that it seemed quite accurate with the 8” heavy barrel. When I switched to a 6” light barrel it wasn’t nearly as accurate with the same loads. After I finally acquired a set of pin gages I found the answer: the throats were all tight, but they alternated in two sizes: too small and really too small. I reamed it to .431” and it is now the most accurate .44 I have. I now also have a digital inside mic and the throats seem to measure about .4318”

So, did you ream the throats .431 or .432 (.4318)? I am not trying to be a smart a##, just trying to make a point or two;

1. Reamings isn't as precise as we think it is.
2. We don't often need things as precise as we think we do.

[ClemY]

So, did you ream the throats .431 or .432 (.4318)? I am not trying to be a smart a##, just trying to make a point or two;

1. Reamings isn't as precise as we think it is.
2. We don't often need things as precise as we think we do.

The reamer was a nominal .431" and the resulting throats were closer .4318", if I can measure accurately. Close enough. They seem to work well for me.