Model 8 Chamber/Ammo question

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45guy
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Joined: Fri Feb 12, 2010 1:29 pm

Model 8 Chamber/Ammo question

Post by 45guy »

This question begins with a purchase from Reed's, I believe, back in 2006. I had ordered some 150 grain .30 Rem which when it arrived was loaded with 150 grain Core-Lokt SPITZERS. Now every factory round, and my own for that matter, have all been loaded with good old RN bullets. Not surprisingly, there was a noticeable difference in performance. So the question is, does anyone here have a dimensioned cutaway of a model 8 chamber to confirm my suspicions?
"The sound of shot sweeping through the air toward you is impressive though. I'll give you that. It's like being swatted with the broom of God."
texassako
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Re: Model 8 Chamber/Ammo question

Post by texassako »

I don't have an answer for you, but was wondering what the chamber dimensions would tell you? I bet they shot a little flatter. You could always do a chamber cast on your own rifle to get its specific dimensions.
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45guy
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Re: Model 8 Chamber/Ammo question

Post by 45guy »

I'm assuming they have a long throat, much like the Remingtons in .257 Roberts. In other words, if you want a spitzer to actually be contacting the lands you would have to seat it too far out to fit the magazine.
"The sound of shot sweeping through the air toward you is impressive though. I'll give you that. It's like being swatted with the broom of God."
DWalt
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Re: Model 8 Chamber/Ammo question

Post by DWalt »

The real issue with using spitzer bullets in the .30 Rem is in keeping the cartridge overall length (OAL) to where it can fit into the magazine (2.54"). I have noted that about the heaviest spitzers (at least that I know of) that will work properly in the .30 Rem are maybe 125-130 grains. Heavier spitzer bullets loaded to maximum OAL to fit within the magazine will have the intersection of the ogive and the cylindrical bullet body below the case mouth. Not actually dangerous, but looks funny, plus the bullet is not too well supported. A longer OAL with a heavier bullet wouldn't be a problem if you single-loaded the cartridges with the bullet loaded further out. I can't tell you just how far out is too far, but it can easily be determined. You just slightly size the case neck so it is a snug fit on a bullet, with the bullet well out, then ease it into the chamber, Ease it back out, and measure the OAL for whatever bullet you want to use. Go about 0.01" less, and the bullet will just clear the start of the rifling. There is also a fairly simple device made that will do the same thing and make more precise measurements possible - used a lot by bench-rest shooters. Those guys like to have the bullet just kiss the start of the rifling as it prevents any tipping of the bullet as it leaves the case, as that could affect accuracy. What you do not want is to jam the bullet into the rifling, as it can raise chamber pressures. By the way, I have loaded RN bullet weights up to 220 grains in the .30 Rem, and they work pretty good, and seem to stabilize. Problem is that you must keep velocities fairly low, as chamber pressures would be very high otherwise.

Please note that every bullet weight and shape will produce a different cartridge OAL to just reach the rifling lands ahead of the chamber. This is because nose ogive shapes are different, the extremes being round and conical. Yes, both are ogives.

I do have the dimensioned SAAMI chamber drawings of almost all cartridges, but I am not where I can access them. They wouldn't help much in answering the question due to the aforementioned differences in bullet profiles and nose lengths from manufacturer to manufacturer and weight to weight.
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