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What is the optimal bearing surface for MG barrels?

Grain weight is mentioned a lot, but from my understanding, bearing surface is the more important factor.


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That is a good question. Cast or jacketed?
I am of the opinion that the ideal bearing surface of jacketed bullets is about the same as the bearing surface of the bullets made for it. If you look at the 240gr Rem bullet and the Hornady 265 fp, I am willing to bet that you would be in the ball park.
Starrbow might be able to offer some insight if'n he makes it around to see this thread.
Ranch Dog talked to me about this issue and as I remember, he said that the RD 432-240/250 is about as short as he would want to go with a cast bullet. Then again, he was looking at more than bearing surface, but taking into account the for/aft weight distribution for in flight stability. There is part of the equation that includes nose length, type and weight into that account as well.
Is that a fuzzy enough of an answer for you? How's this? if your between .30" and .55" with a properly sized bullet, you should be good to go.
 

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That is a good question. Cast or jacketed?
With a bullet of .43-.432" in a 1/38 twist, the ideal weight is between 180-190 grains based on the Greenhill Formula. I have had some success with bullets in that weight, but I am of the opinion that the ideal bearing surface of jacketed bullets is about the same as the bearing surface of the bullets made for it. If you look at the 240gr Rem bullet and the Hornady 265 fp, I am willing to bet that you would be in the ball park.
Starrbow might be able to offer some insight if'n he makes it around to see this thread.
Ranch Dog talked to me about this issue and as I remember, he said that the RD 432-240/250 is about as short as he would want to go with a cast bullet. Then again, he was looking at more than bearing surface, but taking into account the for/aft weight distribution for in flight stability. There is part of the equation that includes nose length, type and weight into that account as well.
Is that a fuzzy enough of an answer for you? How's this? if your between .30" and .55" with a properly sized bullet, you should be good to go.
​Did you mean 280-290gr?
 

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What makes you think that bearing surface is the end all? I don't have the answer as to what is the best surface length, most likely I'm as confused as most. My 350grain AA bullet has a very long unlubed bearing surface, but it shoots great out of a OEM 444, as does the Ranch Dog 350grain with lots of the bearing surface lubed. Cast Bullet weight and diameter, hardness and velocity has way more bearing on how they will shoot VS how long a bullet is in a MG barrel.
 

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Dawei, I looked for the calculator that told me that, but now I cant find that calculator. I compared it to some other calculators and according to them, by bullet's over-all-length, is right between the Rem 240 and Hornady 265 FP, so the 180-190 grain weight ideal is probably incorrect. I wish I could find that calculator now.
I omitted the sentence from the previous post.
 

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My MG handles Remington 240 grain just fine and really shines with a 265 grain. If you take a quick look the 444 was designed to have a reasonably short nose bullet. I've not tried but folks often complain that heavy 44 mag bullets are too long in the nose to use the cannelure. Glen Fryxel does an interesting big bullet test in a MG barrel and discusses the Greenhill formula in detail, based on bullet length though. He suggests the constant in the formula is far too conservative for a MG 444. I really like the 265 Hor FN but one could argue that the MG sweet spot is from 280 to 325 grains. There are enough online tests to confirm this.


Some have described the .444 Marlin as "a modern .45-70", the historical record shows that the basic concept behind
 
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I know I tried the 400gr Razberry bullet in my '65, 1-38 twist 24" MG rifle. At 100 yards, the 400gr bullet, at about 1920fps, had mild but obvious keyholing. I think a similar bullet weighing 375gr could be stabilized.
The 187gr Chino Valley bullet has a bearing length of only about .3" and it is stabilized in the 1 in 38 mg barrel.
 

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Well I am not sure of the bearing surface of my 444S, but I DO KNOW this gun loves 265gr, Hornady Inter-Locks, 5-shot 100 yard groups where all 5 holes touch. This is the first that I have heard of bearing surface mentioned, so I look forward to reading the responses. Good Shooting,----Riflemann
 
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