M29 throats .429/.431 bullets?

[major kong]

I recently acquired a Bisley Flattop in .44 Spl with throats that measure .431 with pin gages. So I ordered some laser-cast 240gr SWC that are .431 to load for it.
More recently I acquired a spanking new M29-10 with throats at .429.
I'm going to load .44 spl brass with the laser-cast bullets over 6.5-7.0 gr of Unique to shoot in the Bisley. I'm just wondering if it would be ok to run these in the M29 also.
My main concern is damaging the gun (and myself). I'm kind of new to reloading so I just want to be sure I don't do anything stupid.
If there is any risk I can always buy bullets that are .429- there are plenty out there. I'm just itching to try out the M29 and these bullets are the ones that I have right now.
Thoughts, advice?

 

[Skip Sackett]

Huummmm.......

Well, Major, I'm not sure just how to answer this. I know what I want to say, but also want to be cautious because I cannot see the condition of your firearms.

First off. I don't think you can hurt a M29 by running any 44Spl load through it, that is, one that isn't a magnum load in a special case!

I have several articles here about sizing cast boolits(lead bullets). One is Phil Sharpe's book from the 1930's. In the revision I have, it is clearly stated that most folks shoot boolits(lead bullets)that are sized to .002" to .003" oversize.


I do too. The Lyman book, #49 has a section on cast boolits(lead bullets) that may help you. Most of the Lyman manuals have a good section on cast boolits(lead bullets) that may be of use for you to read even though you don't cast for yourself, yet!

At any rate, keep the loads in the current data and you shouldn't have a problem. Make sure you chronograph them though. If for some reason, your 6.5gr to 7gr load produces 1500fps, you will know that something is awry. Once you know that, you can make changes to your load.

Hope this helps!

 

[cp1969]

Not a problem--They'll scrunch down just fine.

May not provide the best accuracy, though, and they might lead a little worse than you'd like.

 

[rkrcpa]

I would open the throats on the M29 to accommodate the larger bullet, .429 sounds too tight and could cause leading issues.

 

[cp1969]

I wouldn't modify a M29's cylinder just so I could use a batch of bullets sized for a different gun.

Where in hell is Major Kong?

 

[2hawk]

Try it before you do anything. I have a few older 44mags with throats in the .431 range, and I also have a 629-4 PC Light Hunter with throats at .4285. It shoots my .431 LSWC loads just fine, without leading, and the accuracy is the best of any of my 44's.

I think that some guns just don't know what conventional wisdom is

 

[msinc]

I just picked up my 629 last week. It has .429" throats. I have put about 300 rounds thru it so far, all of which are cast bullets that I sized to either .429" or .430". It does not lead the barrel at all and either size is extremely very accurate. I have found that slow burning powder works better and makes a bigger difference as far as stopping the barrel from leading up than any other thing I have tried. And I have tried many things.

 

[major kong]

Thanks for the info. I'm going to try them out Saturday and see how they do.

 

[Shuz]

I own several Smith 629's that have .428" throats. I shoot .431 diameter boolits outta all of them with excellent accuracy and no appreciable leading. The reason I use .431 diameter boolits is because I also have several other .44 mags that have .431 throats and these guns NEED .431 or larger boolits for both accuracy and preventing leading. A good rule of thumb I use is: Always use cast boolits that are equal to or slightly larger than cylinder throats and NEVER use cast boolits that are smaller than the cylinder throats.

 

[firearmsunlimited]

Major,

First, do not consider opening the throat on your 29.
Second, I believe the throat is actually .428. Beginning with the endurance upgrades in 1988 Smith started taking steps to increase accuracy. In 1990 with the final upgrades implemented they stated messing with various throat sizes. Up until this point throats had been averaging .432-.433 as in the 29-4s. I have seen a 29-5 with .4295 groove and .4295 throat that is a very accurate shooter. S&W found that by going to .428 throats they were able to get even better accuracy as can be found in the Classic DX series. How this is accomplished is baffling since it goes against common logic to squeeze a .429 or .430 bullet down a .428 throat but the DX guns are the most accurate produced to date. Shooting a .431 in a .428 throat is not good. Pressures will sky rocket regardless if you are using .44 special or .44 mag. Additionally the bullet base will not upset correctly greatly effecting accuracy. IMHO I would order .429 bullets for your model 29.

 

[okie john]

What's the bore diameter? Have you checked that yet? Conventional wisdom says that throats should be .001" over bore diameter, but given the success of the DX Classic guns, that may not be as sound as we all thought...


Okie John

 

[firearmsunlimited]

What's the bore diameter? Have you checked that yet? Conventional wisdom says that throats should be .001" over bore diameter, but given the success of the DX Classic guns, that may not be as sound as we all thought...


Okie John

Wrong! SAAMI standard spec lists .4325 throat, .417 bore diameter and .429 groove diameter.

 

[okie john]

Lighten up, amigo. Conventional wisdom and SAAMI aren't the same thing.

I meant to say that conventional wisdom says throats should be .001" over groove diameter.


Okie John

 

[major kong]

Not sure what the bore diameter is--didn't measure it. The throats on my gun measured .429 though, not .428.
Anyhow, I got to shoot it today. I had some loaded over 6.5 and 7 grains of Unique. Accuracy was good with both loads and leading wasn't a problem. It cleaned up easily.