Cylinder throat issue on 629, maybe

[HDS]

OK so I got this lovely custom 629 I bought from a german tuning company called Wischo, well I bought it from one of their going out of business sales.

Anyway I've been shooting hundreds of purchased cast bullet rounds through it the last 6 months and leading has been an issue. 44spl loads, various magnum loads, various bullet weights, I even tried tumbling the bullets in lee liquid alox for extra lube. The barrel I had slugged earlier and measured by a smith with a V-anvil micrometer (due to the 5-groove thing) and he said it was .4287", almost .429" then.

Now I slugged the cylinder throats last night and with my digital caliper I get .428" or .4285" sometimes. Now this is a caliper and not as precise but it does seem that the throats are likely to be on the small side, this could explain my leading issues I think. I need to acquire a micrometer to verify this.

If it turns out they are too small I suppose the solution is to ream the cylinders. I was thinking of reaming them to .430 or maybe .4295" if thats possible. I will be calibrating my own cast bullets to .430", I tried forcing a .430" bullet through the cylinders but it was not possible at all with any amount of hand force. So clearly they are a good bit under .430"

Now that I have explained the background to my problems my questions are the following:

1) To what size should I ream for best function, knowing the size of my barrel (.4287") and the size of the bullets (.430") I will use?

2) Who makes a good reamer, can I get it in the proper size or are they limited in selections?

3) Does anything else need to be done after reaming, IIRC some say that some polishing is needed to get rid of toolmarks? If so how do I go about this?

Thanks for any help.

 

[bgrafsr]

This may be what you are looking for:
REVOLVER CYLINDER THROATING REAMER - Brownells

You should not have to polish the throat after using the reamer, and remember, only turn the reamer clockwise when using it. If you turn counter-clockwise, it can and will dull the cutting edges.

 

[tomcatt51]

Or if you're in the US send your cylinder here: Cylindersmith.com Hand reamed cylinder throats
Size your lead bullets .430", ream the throats .430".

 

[mark454]

My guess is that you measured the cylinder wrong. You should be using pin guages for that. If you decide to ream the cylinder, you might be best off to let this fellow Cylindersmith.com Hand reamed cylinder throats do the work.
Good luck,
Mark

 

[44wheelman]

MSC has some good prices, I've used their stuff in the past.

MSC Industrial Supply Co.

I would recomend USA made HSS... about $40

search part no. 72034309

 

[Alk8944]

HDS,

Don't decide you need to ream the throats based on measurements obtained by two different people, at two different times! The small variation in measurements you give, less than .001", could be the difference in feel each of you used, or calibration of the instruments.

Before doing anything try one more check. This does not involve any measurement so it eliminates that variable. Slug the barrel and then try the slug in the cylinder throats. If the slug passes through the throats with slight to no resistance the throats are just fine the way they are. At least they are big enough! Chances are far greater that the throats in a S&W will be oversize than undersize.

 

[tomcatt51]

HDS,

Don't decide you need to ream the throats based on measurements obtained by two different people, at two different times! The small variation in measurements you give, less than .001", could be the difference in feel each of you used, or calibration of the instruments.

Very true, and a caliper really isn't a suitable measuring instrument for cylinder throats. If a .429" jacketed bullet will slide thru the throat with LIGHT (or no) pressure your throats are big enough for lead.

A zero clearance fit, like a .430 bullet in a .430 throat, is a light PRESS fit requiring considerable pressure.

Just for grins I checked the throats in my much used 629-2 and they're .433 (telescoping gauge and 0-1 vernier micrometer) and a .430 lead bullet just falls thru.

 

[500 Magnum Nut]

Personally, I wouldn't ream your throats more. I'd look into another brand of bullets. I feel the bullets are too soft and are causing this problem for you,
If your getting spitting, use a Lewis lead remover tool and clean the forcing cone after shooting it. They make a tapered cone with a bronze screen that will effectively clean all the lead off the forcing cone. If you ream the throats out even .002 your groups will open up.

 

[HDS]

HDS,

Don't decide you need to ream the throats based on measurements obtained by two different people, at two different times! The small variation in measurements you give, less than .001", could be the difference in feel each of you used, or calibration of the instruments.

Before doing anything try one more check. This does not involve any measurement so it eliminates that variable. Slug the barrel and then try the slug in the cylinder throats. If the slug passes through the throats with slight to no resistance the throats are just fine the way they are. At least they are big enough! Chances are far greater that the throats in a S&W will be oversize than undersize.

I am going to buy a micrometer to test with before I do anything as I mentioned. I just decided to ask the questions ahead of time if it turns out this is needed. I will test this method you mention though.

 

[HDS]

Well I hammered a slug (.430 freshly calibrated bullet) through and then I tried putting it through the cylinder throats. The first throat I tried I could not get it in, the second I tried I got it in with a lot of hand force, the rest after that was easier, possibly because I had swaged the bullet down from the first time I got it in the cylinder throat.

I did not put the bullet in all the way and if I reverse the bullet and put it in base first it wouldn't go in until I tried a few times, then it started going in easier. Again I assume it was swaged down, this time at the base, I tried pushing the bullet all the way through now and hit resistance again around the middle of the bullet and it was impossible to push through without help of a tool.

 

[Alk8944]

Well I hammered a slug (.430 freshly calibrated bullet) through and then I tried putting it through the cylinder throats. The first throat I tried I could not get it in, the second I tried I got it in with a lot of hand force, the rest after that was easier, possibly because I had swaged the bullet down from the first time I got it in the cylinder throat.

I did not put the bullet in all the way and if I reverse the bullet and put it in base first it wouldn't go in until I tried a few times, then it started going in easier. Again I assume it was swaged down, this time at the base, I tried pushing the bullet all the way through now and hit resistance again around the middle of the bullet and it was impossible to push through without help of a tool.

I guess I should have said that the slug was only good for checking one throat! The way to do it is drop the slug into the charge hole and push it through the throat from the rear. If it takes more than a pound of pressure to push it through the throats are too small.

I will be happy to measure a barrel slug for you, send me a PM and we can discuss it.

 

[44wheelman]

Personally, I wouldn't ream your throats more. I'd look into another brand of bullets. I feel the bullets are too soft and are causing this problem for you,
If your getting spitting, use a Lewis lead remover tool and clean the forcing cone after shooting it. They make a tapered cone with a bronze screen that will effectively clean all the lead off the forcing cone. If you ream the throats out even .002 your groups will open up.

I'll disagree with this, to some extent. The chambers on my pre-29's and 29 (no dash) are all larger than a .432 gage pin. The are all very accurate guns. Not that I would encourage anyone to open their throats up that much unless their bore slugs .431+

 

[HDS]

For shooting lead bullets a larger cylinder throat is mostly better, but not too much either, I understand .001" or .0005" is the ideal difference, but it should not exceed .004" or .005" IIRC, then accuracy will degrade.

I don't think bullet hardness is an issue here either, the bullets where 17BHN bullets and thats more than enough for most .44magum levels. They could be several BHN's softer for better perfomance actually, I first suspected the bullets being the cause in this gun and then it was them being too hard I was thinking, as that is often the cause of leading than softness.

 

[500 Magnum Nut]

I'll disagree with this, to some extent. The chambers on my pre-29's and 29 (no dash) are all larger than a .432 gage pin. The are all very accurate guns. Not that I would encourage anyone to open their throats up that much unless their bore slugs .431+

Correct. The picture looks pre -4 so the gun should have large throats already.

OP It's best to check your throats with plug gauges. Then if they are small, go ahead and open them up to no more than .432

If you shoot jacketed ammo in .432 throats, don't expect a target gun.

 

[HDS]

Never will a jacketed round touch this gun. This gun is a 629-5 btw.

IF reaming is required I don't see I should need to ream to more than .4295 or .430", assuming my measurements pan out.

I am making several slugs to send to a person with a V-anvil micrometer. I will also acquire my own micrometer and check the cylinder throats (I slugged them all last night), I will also get those pin gauges you mention to double check.

Then after that I believe I will have enough information to decide on wheter there is an issue or not.

 

[HDS]

Using my black belt in google I've noticed that there seems to be a trend of people complaining about tight throats in 629-5's and someone also mentioning that 629-4s and earlier came with larger throats.

I gather the tighter throats makes this gun more suited for shooting jacketed ammo, but like I said I don't have any plans to let a jacketed round touch this gun, well never again anyway. First box I ever shot out of this was purchased magetch that was jacketed.

 

[Nemo288]

All my .44 Smith's are from the mid 80's. They have .432 +/-
.001 chamber throats. I have shot one hole groups with the proper loads
(mostly lead but copper is accurate too) with most of them.
Those who say a .432 chamber throat is inaccurate is condemning
every Smith made prior to the 629-5 to inaccuratude.

Sorry but that's just too gross an generality for me.
Decades of larger throats can't be wrong

After all, Dirty Harry always hit what he aimed at, right?

---
Nemo

 

[tomcatt51]

All my .44 Smith's are from the mid 80's. They have .432 +/-.001 chamber throats.

I was surprised the throats in my 629-2 were .4330-.4332. I'd never checked them (I bought the gun new) because about all I ever shot was lead and it shot very well. BUT, if I had a cylinder with small throats they'd get reamed to .430 for lead.

 

[Nemo288]

Lake Geneva eh? I'll pack a couple guns in the saddle bags and
meet you if you have a good place to shoot.
They paved my gun club (Middleton) over a few years ago.
All I have left is the hat.

---
Nemo

 

[500 Magnum Nut]

Dash 4 and later have the tight throats, and your correct it's because of jacketed ammo.

Ream away.
The nice thing about using lead is you can control the size of the slugs.

(The picture sure looked like a -1 or a no dash to me, so I figured that it had all ready large throats. No offense, All I see is typed messages on a monitor. I don't know you or your background. Some people can't measure anything accurately and I assumed it to be an older gun with the automatically large throats.)

Shooting jacketed ammo, the -4 and newer guns do shoot tighter groups due to the tighter throats.

I measure the groups on all the chambers not the best three....

Have fun