44 Mag Throat Diameter

murf205 · #51 10-09-2013, 09:37 PM

Well, I finally had enough of S&W's bull spit and bought a Manson cylinder throat reamer and pilot pack. I taped the cylinder with masking tape to write on and numbered each cylinder. Then I used the pilots to see which one was a slip(non interference) fit and wrote the size on the masking tape corresponding to that cyl. Used pipe thread cutting oil and followed the instructions--piece of cake!! Clean the reamer BEFORE you pull it back through the cylinder and do'nt turn it backwards. Mild pressure is all that is needed. I chucked my reamer up in a drill chuck that was not mounted to a drill for a handle and it was perfect. Use plenty oil and go slow. Throats look great, and I'll shoot some loads and report. I called Manson and talked to Dave Manson when I ordered the reamer and he was a huge help. Super nice guy and he could'nt believe what S&W said when I told them that my throats were .4275-.428. Cost was $145 shipped UPS.
Murf205

murf205 · #52 10-11-2013, 10:03 AM

Ok guys, here's my latest on cylinder throats, now that I have decided to forget about the dildoes at customer dis-service. I got the throating reamer from Dave Manson if 3 days. I bought the pilot pack because my 24 had 3 different dia. throats. Wow, no wonder it would'nt hit a bull in the backside. The smallest was [email protected], 3 were .428 and 1 was .4285. I chucked the reamer in a drill chuck not attached to a drill, but Manson sells a tee handle with a set screw that is perfect for the job. I used pipe thread cutting oil and very mild pressure on the reamer and the results were actually smoother than factory cut throats. Use masking tape to identify each cylinder hole and write the pilot size on the tape prior to starting. Check the pilots on a clean throat and look for a good snug NON interference fit. In other words, do'nt force it when your checking pilot fit. Put something under the cylinder to catch the oil and you are ready. Here are my results with a Lee cast boolit and w/gas check sized to .430. Murf

murf205 · #53 10-11-2013, 10:11 AM

Here are Mansons reamer instructions. If you have drilled and tapped anything, you can do this. Just be carefull putting the reamer in past the chamber, but it self centers when the pilot slides in the throat hole.
Murf

murf205 · #54 10-11-2013, 10:14 AM

Here they are.

Boxhead · #55 10-12-2013, 04:58 AM

I would buy some quality hand cast bullets as close to the original Keith design as possible from either Montana Bullet Works and Beartooth Bullets sized to .430" load it to 1100 fps or so (I like HS-6 when running the 44 there) and shoot. I suspect that the gun will shoot very, very well. That said, Cylindersmith does fine work.

murf205 · #56 10-12-2013, 07:59 AM

So far this model 24 has not taken a shine to keith type bullets. The original Keith bullets are a pain to cast(I do'nt buy bullets anymore) because of the square bottom lube groove. Works fine when shooting but they are a bit harder to get to drop out of the mould. It's still a work in progress and I've been using a Lyman 429421 keith mould but I am going to order a custom 250 gr mould from Accurate Molds. The man who makes them does some of the most beautifull work You ever saw on a bullet mould. I've never tried HS-6, but a lot of people love it. I have 5lbs of Unique and of the 12 44's I've owned, I never had one that would'nt at least tolerate it or 2400. When I hit the right load, it usually is the bullet and/or the pressure that makes the diff.
Murf205

murf205 · #57 10-12-2013, 08:02 AM

BTW, Boxhead, Cylindersmith does'nt do anything but .45 cylinders now. He told me that he is trying to get out of the business, so if ya got a .45 that needs opening up, better get it to him.
Murf205

dla · #58 10-12-2013, 12:40 PM

Quote:

Originally Posted by catfish_dan

great info, thanks. I'm just waiting on a reply from S&W before I look to get the throats opened to .430. I emailed S&W asking why the throats are so close to being out of spec relative to SAAMI. In the SAAMI docs, the throat is listed as .4325 +/- .004 which leaves a throat of .428 just barely within. After a reply, I'll be looking to find someone reputable to do the honing.

I am so glad I found this forum because before this I never considered reviewing the specs on my gun. I thought my leading issues were a result of too soft lead. I even went so far as to start electroplating my cast rounds. Came out pretty good too, I was plating 50 rounds at a time with a nice hard shiny coating. I was shocked when I tested the rounds and they leaded horribly too. Live and learn

I might be wrong, but the SAAMI drawing for minimum chamber has a tolerance of +.004, not +/- .004.

Here is the SAAMI 44 mag drawing

But on another note, it isn't trivial to measure the bore of S&W's 5 grove/land system - not something I would try without a ring gauge set. And measuring the throat isn't something one can do accurately with a Harbor Freight expander and a +/.001" caliper.

My point here is that folks should get a pro to do the measurements before getting all excited about opening the throats.

I'd feel a whole lot more comfortable with this discussion if there was some hard data collection taking place. I.e. Ransom Rest BEFORE reaming and Ransom Rest AFTER reaming.

catfish_dan · #59 10-13-2013, 07:50 AM

yup, you're right + .004 so my throats, measured with precision gauge pins from the company I work for QA department are out of spec. I was also working with 2 ex-S&W mechanical engineers that happen to work with me. I live a town over from S&W so there are a few around. I'm pretty confident of the measurement.

As I stated in earlier posts, my issue is not with accuracy but severe leading. I couldn't get through half a box before the leading was so severe that the grooves were no longer visible in the barrel. So I guess that's pretty exciting.

Dan

murf205 · #60 10-14-2013, 09:43 AM

dla, I do'nt use Harbor Freight anything and I DID check the throats with pin guages that I bought from Carr-Lane in St. Louis, Mo. As far as being a pro, pin guages do not require a genius to use as long as the throats are clean. As far as "getting all excited" I did'nt. I just opened the throats from .4275 to .430, which is a lot closer to where they should be and the results were obvious, to me at least. I do'nt own a Ransom rest-spent the money on a throating reamer.

catfish_dan · #61 11-03-2013, 11:17 AM

Just an update and a warning. I received my .44 back from S&W after sending it in with a request to hone the cylinder throats and was shocked at the result. I included a letter when I sent the firearm in to them requesting that the throats be opened to .430 and that if this wouldn't be covered under warranty repair to let me know what the cost would be so I could have them perform the throat work.

When I received the firearm back, there was simply a reply stating "can't prevent leading" and that they cut the forcing cone!!! ???? Note that no one ever contacted me about my request, I simply received the firearm back from FEDEX fairly unexpectedly.

I was also extremely disappointed with the quality of the machining they did perform. The stainless looked grey and all of the tooling marks are obviously visible. No polishing or finish machining.

I am done with S&W and will never consider any firearm from them in the future. I also caution anyone sending anything in to them after seeing the result of their "work" and their lack of communication.

M29since14 · #62 11-03-2013, 11:56 AM

Sorry about the disappointment. I am just guessing but they probably re-cut the forcing cone because they found it to be out of spec. As to the honing of your cylinder, you really should have sent the gun to a pistolsmith who specializes in this sort of thing. S&W makes their guns to shoot factory ammunition, which these days is mostly jacketed. They are probably not going to pay too much attention to requests to modify the gun to shoot certain types of handloads. It's not their thing. They are a manufacturer. Pistolsmiths probably best handle this sort of stuff. Sure, a little communication would have been nice, but that is not unusual for them. About one call in four to Springfield ends up satisfactorily as far as my experience has been over the years. The other three make me wish I was running their C.S. department (

) - but, as I have said before, I can only imagine the kind of calls/requests they must get in the course of a day. Probably would baffle the ordinary mind.

fredj338 · #63 11-03-2013, 01:38 PM

Quote:

Originally Posted by murf205

dla, I do'nt use Harbor Freight anything and I DID check the throats with pin guages that I bought from Carr-Lane in St. Louis, Mo. As far as being a pro, pin guages do not require a genius to use as long as the throats are clean. As far as "getting all excited" I did'nt. I just opened the throats from .4275 to .430, which is a lot closer to where they should be and the results were obvious, to me at least. I do'nt own a Ransom rest-spent the money on a throating reamer.

You did the right thing. 44mag throats that small are just NOT going to do well with cast bullets, unless the groove dia is that small, & that is often NOT the case. The few guns that I have w/ tight throats got opened up & accuracy was improved as well as reducing early leading. Since none of my revolvers see jacketed bullets, proper bullet fit is very important.
BTW, you do NOT need a "professional" to measure anything. Get some pin gages or ID micro. Slug the bbl &/or the throats if you do not want to invest in measuring equip other than calipers.

Nick B · #64 11-03-2013, 04:33 PM

I must have good luck because I've had nothing but great service from S&W's CS department .

KFrameFan · #65 11-03-2013, 04:56 PM

I just used the brownells throat reamer and their 11* forcing cone cutter on my 629-6. I have yet to shoot any lead through the newly opened throats, but can't wait to see the results. Catfish Dan I hope you can get the results you are looking for eventually. I too was slightly disappointed with S&W CS last time I used them.

Nick B · #66 11-03-2013, 05:59 PM

Quote:

Originally Posted by murf205

Here are Mansons reamer instructions. If you have drilled and tapped anything, you can do this. Just be carefull putting the reamer in past the chamber, but it self centers when the pilot slides in the throat hole.
Murf

After you ream the throats do they need polishing ?

Tom C · #67 11-03-2013, 09:01 PM

I have had pretty good luck with the S&W service department in the past.

I had to ream a bunch of .45 Colt and .45 ACP cylinders for my Ruger NMBHs. Most were very tight. All shot much better after being opened up to .4525” or so.

My Dan Wesson 744 had throats alternating in two sizes, both very small and accuracy was pretty poor. I got the Manson reamer and reamed them to .4315” and it is now the most accurate .44 I have.

My 629 Mountain Gun had the usual rough forcing cone and very tight chamber throats. I recut the forcing cone and reamed the cylinder. It is much better now.

dla · #68 11-03-2013, 09:07 PM

Quote:

Originally Posted by fredj338

You did the right thing. 44mag throats that small are just NOT going to do well with cast bullets, unless the groove dia is that small, & that is often NOT the case. The few guns that I have w/ tight throats got opened up & accuracy was improved as well as reducing early leading. Since none of my revolvers see jacketed bullets, proper bullet fit is very important.
BTW, you do NOT need a "professional" to measure anything. Get some pin gages or ID micro. Slug the bbl &/or the throats if you do not want to invest in measuring equip other than calipers.

How do you measure the slug for a 5 groove barrel with calipers?

ElmerKeith · #69 03-19-2014, 05:42 AM

Quote:

Originally Posted by BLUEDOT37

You didn't say exactly what they measured & tight to exit isn't very specific. If you can measure the throats & post it that would be helpful.

My 29-2 has .4325" throats & has always been very accurate with .430" cast lead & 17gr/2400 for some reason. Wish my SRH 454 was as good.

Excuse me for digging this out but I have the chance to get a M 29-2 with a 6" bbl. and have some concerns about the accuracy departement.
Although I don't want to wait until someone somehow will appear with a M29-5 to sell.

What type of cast bullets do you use in your M29-2 with the slightly ovesized throats.

BLUEDOT37 · #70 03-20-2014, 02:08 AM

Quote:

Originally Posted by ElmerKeith

What type of cast bullets do you use in your M29-2 with the slightly ovesized throats.

I've never gone out of my way to order anything special. I've anyways just bought whatever brand I could find in .430" LSWC Keith style or BB bullets. I just bought some (500) Rim Rock 240gr cast SWC-BB that measure .4305". (They also have the more preferred Keith-FB in 260gr in .430 or .431" but are more $$.) I haven't loaded these 44s up yet but the 41s I got from them shoot good & they do ship fast.

fredj338 · #71 03-20-2014, 11:25 AM

Quote:

Originally Posted by dla

How do you measure the slug for a 5 groove barrel with calipers?

For cyl throats, not an issue. For the bore, use a long slug & be very patient.

BongoBoy · #72 02-02-2015, 12:38 PM

Deleted--bad data on my part.

BongoBoy · #73 02-02-2015, 12:39 PM

Was unable to delete these two messages--my apology. No value added.

gaijin · #74 02-02-2015, 02:25 PM

My experience has been all of the newer S&W .44 mag. and .45 Colt cylinder throats are substantially undersized as well as Rugers .45 Colts (I have no experience with Ruger .44's).
I agree with others that ideally, the throat diameter should be real close to bullet diameter to reduce leading and maximize accuracy-with cast bullets.
Since all I shoot is cast from my .4X caliber handguns (they are hunting revolvers) I open the throats to .431" in .44 and .4525" in .45 Colt.
I purchased Manson throat reamers for this purpose.
The accuracy increase ranged from noticeable to substantial, leading is not an issue. This with cast bullets obviously.

shocker · #75 02-02-2015, 04:10 PM

My Model 69 throats slugged 0.4295", call it 430 for practical purposes. Same bullets that performed well in a 29-2 made 1980, a 629-5 from the 90's, work in the 69, 430 cast.
I know it's not kosher to measure a 5 groove barrel with calipers, but I tried it anyway. I can catch what feel like 2 edges on the slug and get 429".

ironhead7544 · #76 02-03-2015, 06:02 AM

You need special equipment to measure a 5 groove bore. Best thing to try is slug the bore and see if it fits into the throats. If it doesnt fit, then you may have a problem.

A gas check design can fix a leading problem. I would try that before reaming. Lots of good info at Cast Boolits website.

Lead Bullet Technologies makes good slugs for checking throat and barrel diameters. You dont have to beat it into the bore.

M29since14 · #77 02-03-2015, 10:16 AM

Quote:

Originally Posted by ironhead7544

A gas check design can fix a leading problem...

"A sixgun bullet needs a gas-check like a hound dog needs two tails!"

(or something like that

)

The old man (Elmer Keith) said it years ago and we all laughed. It's still funny to me - and true!

Forrest r · #78 02-03-2015, 05:56 PM

I use a little shim stock rapped around the 5-groove slugs to measure them.

Shim stock ='s a strip of metal cut from a beverage can. Measure the thickness of the aluminum strip that was cut from the can. Rap then thin al strip around the slug and measure it. Subtract 2x the al strip from the slug/al strip measurement : IE the al strip measured .003" the slug with the al strip wrapped around it measured .436". .436 - (.003" x 2) ='s .430"

BLUEDOT37 · #79 02-04-2015, 03:24 AM

The way I check a 5-groove is first find out what the bore dia." (a) is using my pin gauge set. Then I use my telescoping gauge to find the dia." from an opposing groove -> land (b) - (each groove is directly opposite a land). Then I subtract that reading from the first (a) to find one groove's depth (c), then double that number & add it to the first (a).

(a) - Bore dia. = .4438"
(b) - groove->land = .4481"
(c) - .4481-.4438= .0043"
(d) - .4438 + .0043" + .0043" = .4524"

It's kinda tedious, but it works if you have the tools.

.

pcmacd · #80 04-16-2023, 04:00 PM

Quote:

Originally Posted by elundgren

I did a careful measurement of the cylinder throats on my 629-4 MG today using an expanding ball tool and a micrometer. It seems that they are .4293 give or take a tenth or so. My bore groove slugs out at .4296-.4299. It would appear that I need to have the throats reamed out a bit. I have seen a link here to a fellow who calls himself Cylindersmith, has anyone used his services and is he still doing it? Another question. When I shoot .430 jacketed XTP bullets out of this gun what is it doing to the cylinder and to the pressures getting through the throat? If I have the throats reamed out to .4305 will the gun have problems shooting .429 jacketed bullets accurately?

My 2001 vintage 629 8.75" barrel throats gauge with pins @0.428".

When shot with 0.4295" sized bullets its accuracy is superb, so why fool with it?

Hell, the first two of my own hard cast LEE 429-240GC with my first 44 mag loads out of that new revolver both scored bullseyes @25 yards.

Nothing needs fixing here.

Luke Duke · #81 04-17-2023, 02:15 AM

I'm going to have to agree with A couple of guys on this thread. Last year I bought a 629-6 4" barrel. Gun is super tight everywhere. Especially the cylinders. Mine are .428ish. My gun shoots awesome, .430 Hornady or .4295 Seirras. I size my cast to .429 and have had zero leading. I'm not pushing them hard less than 1,000 fps. At first I was concerned but after shooting it; the concerns went away. Sometimes I think we get to caught up in numbers and read to much into it. I talked to customer service and they told me it was in spec and to just shoot it. Tight cylinders for sure but its a shooter.

BillBro · #82 04-28-2023, 09:36 AM

Quote:

Originally Posted by catfish_dan

Hi,

I have 629 MG and recently starting loading cast bullets since I live in Mass and getting components for ammo has become a real challenge.

My first batches resulted in some fairly extreme leading problems, 240gr SWC with 12g of Blue Dot. After half a box the grooves were no longer visible. This was a load worked up by a relative who had good results with it.

I first started looking at my lead alloy since this was a new load for me, and then asked my relative to put some through his Ruger. He had no issues at all with the ammo.

We then took a look at the throat dimensions and I was surprised to find the throat was so tight, similar to what the OP was reporting. After measuring the cast rounds (.430) it seemed awfully tight in comparison with the throat. The Ruger was relatively loose so much so that the .430 cast bullets could be dropped through the cylinder with ease whereas my Smith couldn't even get the bullets started.

To be able to shoot cast, should I be resizing the cast down to .429 or maybe even .427? I really can't afford to shoot purchased ammo, if I can even find it at the moment, so any recommendations would be appreciated.

Thanks,

Dan

Quote:

Originally Posted by M29since14

Dan, most folks seem to think the bullet should be sized to fit the throats (exit bores) of your cylinder, or maybe 0.001" bigger - as long as you can seat the loaded cartridges in the chambers without a problem. I think the theory here is that the base of the bullet can receive a lot of damage before it leaves the cylinder if it is not a good fit for the exit bores. I tend to agree with this. Whenever my cast bullet loads are properly sized for the exit bores of the cylinder, I have very little trouble with leading and poor accuracy. Just make sure your loads easily "drop in" to the chambers.

The OP's gun sounds fine to me. I would not make any adjustments to the exit bores.

Ive only been shooting cast for about 2 or 3 years and this basic but sound advice is what Ive lived by and it has served me well. I can go to the range and shoot several hundred rounds and maintain good accuracy the entire time, did it yesterday.