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G'day fellow 45Coltmen,

What is the usual nominal bore size in recent 45Colts :?:

Really don't want to "bore-slug" as longer round type sinkers are rare as hen's teeth here in Oz, ie. egg shaped ....... predominantly ball & flat oval types. I've also read it's not always accurate.

Ulimately, I want advice on which projy diameter to choose for accuracy, .452 or .454" in resin coated 250gr LRNFP(1600-1800fps rating)? Is the .454 unsafe pressure-wise at 1500-1600fps?

Seems Aussie 45Colt usage is mainly CAS, lower speeds and short range, higher velocities being uncommon as this cal isn't really used as a hunter here. Shop shelf stock are smaller dias under .452. The pills I have are on the small side, under .451, good at 25yds and all over paper at 100yds.

Thanks
Mucus
 

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G'day......slugging a barrel is no big deal. You can use a blackpowder ball or a fish sinker to slug while using some lube oil and a wood dowel to push/tap the slug thru. Sometimes it is helpful to roll the lead slug between two pieces of flat steel to shape it cylindically or reduce its size a bit before starting the slugging. My rossi mod92 in .45colts slugged at .452/.447: groove/land. Thus, I use .452 lead projectiles and would use .453 sometimes and .451 jacketed bullets with good results. Slugging can reveal tight and loose spots along the barrel plane, too. I don't have any experience with microgroove barrels...but suspect a tight fitting bullet is preferrable.


...............TM7
 

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Should be .452, although I've seen some statements that .454's solved some problems. I've used .452's since I got mine and have had no problems with them.......Buck 8) :roll: :wink:
 

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Should be .451 groove dia as that is now SAAMI standard. .452" bullets should work. They work in my EMF Rossi 92 in .45 Colt.
 

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Mad,

I used Cerrosafe, a low temperature melting alloy to check my '94 bore - .452". You put a patch on a cleaning rod and insert it into the barrel from the muzzle, stopping the patch 40 to 50 mm from the breech. Melt the cerrosafe with a hot air gun and pour it into the chamber. Pop the solidified slug out with the cleaning rod after a minute of cooling and wait half an hour to measure the slug with a micrometer. The alloy first shrinks then expands during the next several hours. It is supposed to be the size of the rifle bore in about 30 minutes. So don't leave it in the barrel long.

The older 45 colt pistols, pre 60's or so, used to have barrels around .454" and the 45 ACPs were .452 or there about. The growing popularity of the 45 ACP at the time shifted 45 caliber pistol cartridge barrel bores to .452". It was about that time that revolvers with cylinders for both cartridges appeared.

You should be able to shoot a .454" lead bullet in your rifle. It may even prefer them. SAAMI bullet specs are .456 - .450"

Depending upon the hardness of your bullets and the efficacy of the bullet lubricant, those 1800 fps speeds may be in the range where a gas check may be needed to help prevent leading.

Do you have any information you can share regarding 'resin coating'? Is it something like the liquid alox tumbling that the Lee reloading people promote?

Figure out what that rifle likes and start casting your own bullets.

Regards,

Hudson
 

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Mad Mucus,

My .45 Colt Marlin Cowboy measures .4525" groove dia. I bought it in 1997. It prefers .454" over .452" bullets. If .454" bullets chamber ok (I'm sure they will), those are the ones I would go with even if the groove dia. might be .451".

A bullet sizing down to the smaller bore diameter does notpressures at all in my experience... well, maybe 500 c.u.p. which is insignificant.

I have shot bullets as big as .457" though my .45 Cowboy with excellent accuracy at 30,000 c.u.p. with no problem whatsoever.

w30wcf
 
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