What diameter .44 cast bullets do you guys use. I want to order some more hardcast bullets from Beartooth Bullets. My Marlins seem to prefer .432 Dia. And before you say slug my own barrel I'm not about to pound a piece of metal down a Pre 29. Thanks in advance

Actually, most serious caster would want to know the size of the chamber throat, sonslug the chambers. That will give you the minimum size.

Kevin

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Your Marlins prefer 432 because SAAMI specifies larger bores for 44 Magnum RIFLES.
As pointed out above, throats should be slugged. Hornady for one makes 433 diameter lead balls. Ideal for slugging throats and the barrel.
From Penn Bullets on sizing - S&W were generally tighter (than Rugers) and .430 for cast will usually work fine. If you have an early gun from S&W it may be a good idea to have it checked as it may need .429

I have S&W, Ruger and a Marlin 336 in .44 Magnum. Like yours, my Marlin will give excellent accuracy ~1.5" with selected, gas checked cast bullets [Lyman's copy of the Thompson designed 429215gc & 429244gc] but only if dia. is kept to 0.432" or more. Using moderate loads of Unique, Herco and 2400, with velocities not exceeding ~1100 fps, I've shot 0.432" dia cast bullets through both manuf's. guns. Accuracy is down around 1.5" at 25 yds with no sign of over pressure nor visible damage to the guns. Again....with moderate loads.

Throats on the Rugers [a trio of .44 special Flat Top BH's, and a pair of .44 Magnum BH's] run 0.431". Sizing my cast bullets to 0.430" vs. 0.432" makes no discernible difference in group size, nor bbl./throat leading.

The throats on my 2 sons' M29's, as well as my M69, M629, and a M29 Classic pre-lock all run 0.430".

Alloy for the above is straight wheel weight with about 2% tin added for mold fill out. Leading is non-existent as you'd expect with the annealed gas check.

Additionally, I have used and like Lyman's 429421 copy of Keith's design though it drops from the mold at 0.430"...too small for the Marlin, but works well in the handguns. Too, Mihec's excellent 432256 copy of the old H&G 503 design does equally well in my short guns but gave up trying to get a non-GC'd bullet to shoot in the Marlin.

Pressure levels are impossible to estimate without the necessary equipment, alloy content, lube type, friction surface area, & bore condition; hence my self-imposed limit of mid-level loads. They work for me and my guns and I reserve factory jacketed bullets for full house magnum loads & hunting.

Without knowing the condition of your pre-29, I can't recommend a diameter...and you'll have to slug the throats to get the information needed. I'll repeat that 0.432" works for me, but I'd size for 0.431" were I only loading for the revolvers.

YMMV, Best regards, Rod

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Slugging barrel is totally irrelevant unless it is bigger than the throats in which case the gun is a paperweight and I have never seen that on any SW.

Also slugging throats is no good as you will not be able too precisely measure the resulting slug with your average caliper. Either you buy pin gauges or get samples from casters of different diameter bullets. Or just buy 100 each in different sizes. Drop them into the chamber. If they fall right through, go bigger. If they can be gently tapped through with a pencil perfect!

My guns throats from 1977 to 1992 are all between 0.432 and 0.4325.
After 1994 (29-6 and later) precisely 0.429

0.432 may give you likely good results. 0.433 will be hard to find. I think only Montana has one mold suitable for it.

I think model 29s were better in this aspect than the model 25s, those were all over the place...

I get best accuracy with wheelweight alloy bullets of .432" diameter in a couple of Model 29s (older guns from the 70s & early '80s) and in Model 24-3s. However, .431" bullets do almost as well. If that's all that were available, .431" would be fine for my use.

No need to slug a barrel. Check your cylinder throats for bullet fit. As long as a bullet will pass through with no more than very slight resistance, it should work.

Try the softest bullet that fits and doesn't lead the bore; that's a good place to start for best accuracy.

Throat diameter is critically useful to know.
You can get a precise figure(s) using an adjustable small hole gauge. This is cheaper than a set of pin gauges.
Starrett makes an excellent one. Their "Size D" gauge measures holes from 0.400"-0.500".
You use this tool in conjunction with a dial caliper or micrometer.

Jim

PS: if you use a Speer swaged lead roundball in 0.433" diameter, you would find they tap down the barrel (or through the cylinder) with very light effort. Just use a length of 3/8" dowel and a wooden mallet.

The cylinder throat will tell you what diameter bullets to use. My 629, my Ruger SBH, Dan Wesson all have cylinder throats of .431", and groove diameters of .429" and .430". I size my cast bullets .431", any larger and the bullets are sized down when passing the throats and lead "spray" on the cylinder face and frame, and any smaller there is often leading. SAAMI specs. for 44 Magnum rifles is .431" groove diameter and my Puma measures .432", so I size bullets for my Puma to .433". My Contender has .429" groove diameter and a .430"-.431" bullet works quite well, with little or no leading...

When slugging a barrel I prefer a slug at least .005" larger than groove diameter and .010" is better. (I have used 44 Magnum brass for slugs; fill the case with lead, cool and remove slug with an impact bullet puller. Perfect size for my 44s. Same with 38/357). Wooden dowels have been known/reported to break and splinter and jamming in the barrel so I use brass rods. Several places to find brass rod, and 1/4" works well. I bought it in 6' lengths for less than $20.00, but shop around. I cut my rod into 12" lengths for my handguns and 36" for my long guns. Also handy to have at the range in case of an OOPS (squib)...
brass rod - Google Search

All the model 29/629/24/624 revolvers I have take a .430 diameter.

What I was taught to do is take a bullet and drop it in the cylinder. If it falls through it's to small. You should have to push it out of the cylinder with a pencil or wood dowel with a gentle push.

The above method is what I was taught and have used for 25 years.

As you can read from the responses, .431 or .432 will get you good results.

What is your objection to slugging the cylinder? Do you think it will be harder on the revolver than touching off a loaded round?

Kevin

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OK .430 it is.

I size all my cast bullets to .429 for all of my 44 magnum firearms...........rifles and revolvers. Excellent accuracy too! Slug your bores.