44 mag with undersized cylinder throats

[mtgrs737]

My plug gage set came the other day so tonight I thought I would give them a spin. Not so sure I should have now, the throats on my new to me 629 would not pass a .429" +.000 -.0002" gage. They would pass a .428" gage with a little wobble. The barrel slugs .429" as best I can measure. My guess is that the throats are at goove diameter and maybe a few tenths less. I am sure that this gun would shoot J-word bullets just fine, however I am a cast boolit man and shoot cast boolits almost exclusively. Measuring my sized cast boolits yeilds .4305" to .431" . I am thinking of reaming my throats to .431".

1. Is this hard to do myself?

2. Do I need to ream the forcing cone also, and what size or taper would be best?

3. Will the larger throats reduce pressures in the cylinder?

4. How will J-Word bullet accuracy be effected?

5. According to my measurements even the J-Word bullets would be sized down by this cylinder as some Remington bullets I have measure .430".

6. Where is the best place to get both a .430" and .431" reamers?

7. Has anyone here had throats reamed and by whom? I may send the cylinder out if the price for reamers and a handle is too much.

[454PB]

If the throats are that tight, any jacketed bullet that protrudes into them is going to prevent chambering. Have you tried pushing a .430" jacketed bullet through the throats?

[44man]

If you are sure the bore is .429 groove to groove ( The S&W is hard to measure with 5 lands and grooves.) I would go with .430 throats and boolits.
You can lap each throat with a slotted rod wrapped in fine emery mounted in a variable drill for a snug fit. Lap until a .430 bullet will just push through with your thumb. Do not let the emery go into the chamber itself.
"J" bullets will be more accurate too.
Leave the forcing cone alone.
Cylindersmith will do it for you too.

[mtgrs737]

454PB, Yes I have tried to push a jacketed .430" bullet through the throat from both ends and it is a no go. I cannot get a .429" +.000" - .0002" plug gage into the throats either. I just now checked the Brownells catalog and they say that .431" is what the reamer they sell for 44 mag is sized to ream the throats to.

[nicholst55]

Spend the $30 and have Cylindersmith do it. You'll be glad you did!

www.cylindersmith.com

[Lloyd Smale]

yup its easy to get them out of round trying it yourself. Either buy the reamer or have the cylindersmith do it for you. hes cheap and the turnaround is fast. I would have him do them at 4305
Spend the $30 and have Cylindersmith do it. You'll be glad you did!

www.cylindersmith.com

[mtgrs737]

Thanks guys! I didn't know about the cylindersmith! I will check him out!

[Willbird]

Yaknow, it occurs to me that you just might want to shoot it before you alter it ?? If the throats were .425 or something I would be worried, but it may in fact shoot really nice. Smith uses a roller burnisher to finish the cylinder throats and that finish is smoother than any reamer will ever be.

Bill

[mtgrs737]

I shoot .431"+ boolits and those .428"+ throats will do me no good. I can't begin to get a factory jacketed .430" bullet to pass through the throats of the cylinder, so I figure it has to raise the pressures a bit. I sent it along with two other cylinders to cylinder smith for reaming and honing, I will burnish the throats when they get back if needed. Thanks to all who replied, I appreciate it.

[mtgrs737]

I got all three cylinders back from the cylindersmith today! The 45 Ruger now gages .453" the S&W 357mag now passes a .359" gage, and the 44 S&W now passes a .430" loosely but not a .431" gage. The 44 is most likely just under .431" like he said it would be as his reamer is .4305" and he said he would hone it to add a few tenths. My 44 boolits are sized to .431" and will not pass freely through the throats. I think I will polish the throats until I can get a .431" boolit to pass with light finger pressure. I have two other S&W 44's one gages .433 and the other .434". I would like .4315" for just a bit of clearance for fouling but I really don't think that more than .001" would be wise. I don't shoot many jacketed bullets and I like my lead slugs to have free passage through the throat to keep pressure spikes down. What do you guys think? How much clearance should I figure on if any?

As far as I can tell cylindersmiths work is top notch and FAST! I would recomend him just as many of those here have to me. Thanks!

[felix]

Tight boolits require slower ignition when performance is required. Pressure spikes are OK when the very fast powders are used for "light" loads, because the duration of the spike is so short. ... felix

[cbrick]

I wouldn't polish the throats out any more than they already are. A Cast boolit should be a mild snug fit in each throat. If you use a .431" sizing die and depending on your alloy the sized boolits should be a few tenths under, about.4307" or so with WW alloy. If you place a sized boolit in each throat a mild snug fit is where they will stay there but can be tapped out with mild tapping with the erasure end of a pencil. NOTE: NOT a punch and hammer. This won't raise pressure or at least not enough to worry about. If your using a bullet long enough the front driving band (sized to this mild snug fit) will already be inside the throat when chambered and be a reasonable seal to the igniting powder. When the base driving band is in the throat with a mild snug fit the front driving band is now in the forcing cone and you still have a goos gas seal. In addition, with the bullet properly fitted to and in the throat when chambered the bullet is in as good alignment with the bore as you can get.

If your measured groove diameter is .429" or even slightly larger you should be in revolvers heaven. This is where it should shoot it's best.

Rick

[mtgrs737]

Cbrick, I may do a test, to see if boolits sized .430" shoot better than boolits sized .431". Who knows maybe the smaller boolit will shoot just fine and I won't have to mess with trying to get a half a thousandth polished/sanded out of the throats. I have a 7/16" solid brass rod being shipped to me so i can make a lap to do the work. Thanks for your advice.

[Char-Gar]

It will do no harm to shoot sixgun cast bullets that are larger than the cylinder throats. They will size down in the throats. There won't be enough increase in pressure to make any kind of difference. Size them in a die, or size them in the sixgun...allee same..allee same! As long as the cylinder thoat is the same size as the barrel groove diamter you are good to go. I will bet the ream job your did was unnecessary to get good results. Quite often these sixguns don't read gun magazines or internet board and will shoot just fine, even though our theories say they won't.

[Willbird]

It will do no harm to shoot sixgun cast bullets that are larger than the cylinder throats. They will size down in the throats. There won't be enough increase in pressure to make any kind of difference. Size them in a die, or size them in the sixgun...allee same..allee same! As long as the cylinder thoat is the same size as the barrel groove diamter you are good to go. I will bet the ream job your did was unnecessary to get good results. Quite often these sixguns don't read gun magazines or internet board and will shoot just fine, even though our theories say they won't.

I read recently where somebody measured the lead alloy bullets in factory 45 colt ammunition, they measured a wopping .457". This ammunition was also quite accurate.

Bill

[44man]

I would leave the throats alone as long as your rounds chamber. I would trust Cylindersmith to have it right. Shoot those .431 boolits, bet the gun will do 1/2" at 50 yd's!
Don't get wound up tight as long as the throats are over bore size. If rounds won't chamber, get a .430 size die.

[Char-Gar]

Willbird-- One of the deep dark secrets known to those of us who are dyed in the wool sixgun people has to do with the subject at hand. Some of us own a dozen or more sixguns chambered for the same round. I own scores of sixguns and it is beyond my tolerance for details to load ammo for each sixgun in the fleet.

I size the bullets for the largest cylinder throats and let the bullets size down in the other smaller throats. I size all 38/357 bullets .359, 44 spl and mag, .432 and 45 Colt and AR bullets. .455. As long as the round will freely chamber there no problem.

I stoped being overly concerned about pressure issues when some years back when I watched Jim Taylor drop a 45 Colt cylinder in a Ruger 44 Magnum Blackhawk. He fired six rounds of stout Buffalo Bore ammo and his the target each time at 25 yards. He ejected the cases and droped a couple in my hand. The primers nor the cases showed any signs of high pressure. If you can push a .454 bullet down a .430 barrel with normal range of pressure, then a bullet a couple of thousand larger than the cylinder throat is of no concern.

All to often we shooters fixate on the technical theory and ignore the reality of what takes place in real guns fired at real targets. There is so much BS and theory in the gun magazines that folks take as "holy writ" and it gets passed on over and over until it becomes unquestioned. We rifle cast bullet shooters on this board have exploded many of the myths and old wives tales that have been taken as truth for generation. There is allot of the same malarky around dealing with sixgun cast bullet loading as well.

[Bret4207]

Aw comon' Chargar!!! You keep letting the deep dark secrets out and no one will pay money for G+A, GUNS!, Shooting Times, etc, much less listen to the hooey on the dozens of websites and forums saying cast always leads and is inaccurate unless the boolits are hard as diamonds!

Sheesh!!! What's next? Ya gonna tell my kids the truth about the Easter Bunny?!?!??!:mrgreen:

[leftiye]

MTGRS737, Get a piece of metal rod. Turn it down to approx .020 smaller than your chamber mouths(.409). Put it in a vise and hacksaw a slot down the middle of it for about an inch and a half. Put it in your hand power drill. Stick the end of a piece of sandpaper in the slot, wrap the remaining sandpaper around the rod away from the direction of rotation, trim the sand paper length until it will rotate into the chamber mouths with moderate (can be quite tight) tightness. Insert your tool into the chambers from the rear for maximum straightness. The point being, if you only want to open them up a thou., you don't have to ream. For a .429 barrel a .430 chamber mouth is ideal.

[mtgrs737]

Leftiye, I have a 7/16" solid brass rod coming in the mail for just that purpose. I will turn the end to the proper diameter to fit the throat with the wet or dry sand paper in the slot, I only need a couple of tenths. I don't want to chance making them out of round either. I respect and appreciate the information given here by these fine folks, their words have not fallen on deaf ears. I know that my efforts may not make any difference in the accuracy or the chamber pressures that the gun creates but the enjoyment of trying to improve the weapon for our cast boolits is what the effort is really about. The throats were in the neighborhood of .428" when I sent the cylinder off to the cylindersmith. S&W five groove barrels are so hard to measure I could not be sure what the bore diameter is to less than .002" with the tools I have available, so I am making sure that the boolit is as large as possible when it enters the barrel. Again thanks for the inputs I really appreciate them!

[Shuz]

I have not measured the bbl diam because of the difficulty with 5 land/groove dimensions.

Here's what I have found by actual shooting today..... Saeco 446-A, .429 boolits, Saeco 7 hardness, lubed with Lars, White Label lube and 8g of NM-04 leaded my bbl quite a bit. The bbl was easily cleaned out with 7 rounds of 429215GC's (sized .429)and 19g of WC820. The same 446-A boolit and hardness,sized .431 and with 8g of NM-04 leaded the bbl a LOT LESS! How much less I can't measure, but it was less.
Now, current wisdom says to size your boolits to fit your throats, and hopefully if your bbl is the same size or slightly smaller, you should not experience leading. I don't have a .428 0r .427 sizing die, so I went with .429.
What amazes me is that .431 boolits which should have been sized down to .428 (or less?) by the cylinder throats, did not lead as badly as the aforementioned .429 boolits which were closer to the dimensions of the cylinder throats!
Anyone care to postulate why this happened?
I tried this twice with 15 rounds and experienced the same thing.

As an aside, accuracy offhand at 25 to 40 yards, "seemed" to be a little better with the .431 boolits than the .429's. By "seemed", I mean more beverage cans "jumped" in the 1-1/2 feet of snow!

[AzShooter]

If your cylinder throats are smaller than your barrel you are swaging your bullets at the throat and then they will be too small for the barrel.

It's quite common on the Smith's I've tested lately.

I opened the cylinder throats myself. It wasn't difficult but I used a drill press, not a hand drill and went very slowly. Now they are all exactly the same size and measure in my 627 .358 while my bore measures .356.

By having the throats correct the bullets will line up with the forcing cone the way they are suppose to. Your accuracy will improve.

Great book on this is "How To Get Jacketed Accuracy With Lead Bullets" by Veral Smith.

http://lbtmoulds.com/

[leftiye]

Oh yes, it will make a difference. I've heard it said that it may or may not have any effect. It has in my experience made a difference every time to get groove to chamber mouth sizing correct (and of course size boolits correctly in respect to chamber mouths), and to polish forcing cones, and whatever else you can find means to do to finish the manufacturer's job for him. Ground squirrels at 60 yards with a .38 Special anyone?

If you're only taking out a thou., it's very unlikely you'll be able to get anything out of concentric, or crooked.

[mtgrs737]

Oh yes, it will make a difference. I've heard it said that it may or may not have any effect. It has in my experience made a difference every time to get groove to chamber mouth sizing correct (and of course size boolits correctly in respect to chamber mouths), and to polish forcing cones, and whatever else you can find means to do to finish the manufacturer's job for him. Ground squirrels at 60 yards with a .38 Special anyone?

If you're only taking out a thou., it's very unlikely you'll be able to get anything out of concentric, or crooked.

I am sure you are right about the out of concentric or crooked throats. I only intend to open up the throats so that a .431" lead boolit will pass with light finger pressure. I have already sent the cylinder to the smith to open it up from the .428" dimension because I know that I would mess it up without the proper tools, I wish he could of finished the job to .431". I have two older smiths that gage .433" and .434" and they shoot well. I plan on making a special lap out of the brass rod when I get it to finish the job, I plan on working from the chamber end and carefully opening them up. Half a thousandth isn't much but it is stainless steel and that is pretty hard, I don't mind spending the time to optimize this revolver. Will it shoot any better because of the time and money spent on this last bit of throating? Probably not, but it is a hobby for me. Next I will look at the forcing cone to see if anything need be done there.

Thanks guys for all your inputs, they are greatly appreciated!!