Cylinder throat fit for bullets....slip fit or tight???

[Mus408]

I keep reading that for best results in bullet performance the bullet should just slide in the throat with finger pressure.
But then I hear some folks say the bullet should be a tight fit as in .001 larger than throat size which is not going to slip right in.

Often hear that the cylinder should not be acting like a sizer before the bullet gets to the barrel.

On my various .44 Special and Magnum revolvers a .430 bullet that actually measures .4305 will drop right thru all the cylinder throats which measure out to .432-.4325 and they shoot well with no leading issues.

So which is it??

I'm with the slip fit crowd!

 

[tsubaki]

This only pertains to soft cast bullets.
You want the cylinder to be very slightly larger than the groove of the barrel.
The barrel groove should dictate the cylinder dimension needed.
Adjust the cast bullet to that dimension or very slightly larger.

 

[tsubaki]

Jacketed bullets will be slightly smaller in diameter and may not completely obturate to the groove but just enough to engrave from the lands in the barrel.

Careful inspection may be pertinent when purchasing a used revolver, it could have been cylinder reamed for the benefit of using cast bullets only.

 

[gramps]

I drop the lead bullets in the cylinder. If it stops then that is the correct size. No leading here. I don't mess with bore size.
gramps

 

[daveg.inkc]

In Jerry Kuhnhausen's book, "The Ruger Single Action Revolvers",,, he writes to have .001" clearance on throats. No reason to have tight, undersized cylinder throats that I can see.

 

[Luckyducker]

I size throats so that bullets will almost drop through but not quite. I am talking bullets cast .001" over published groove diameter. This works for me, but if you are shooting cast without leading your revolvers bore I would change nothing; just shoot it as is.

 

[grobin]

Well the common thinking is that cast and plated bullets with a hollow or concave base will expand to engage the lands in the barrel if they are slightly over size ~0.001. I don't have an explicit reference. But I agree with the book mentioned above. There is a theoretical concern that a tight cylinder throat will interfere. Hodgon mentions the need to use cast or plated bullets on their site when talking about developing Trail Boss loads. See https://www.hodgdon.com/resources/data-sheets/ TRAIL BOSS REDUCED RIFLE LOAD.

 

[mikld]

"Drop through", "push through", snug, loose whatever, are not measurements. I prefer to know the diameter of my revolver throats so I either use pin/plug gauges, ball gauges, and I have slugged cylinder throats (prolly the easiest). For the best starting point, size or purchase your cast bullets the same diameter as the cylinder throats. While you're slugging, slug the barrel to make sure the groove diameter is smaller than the throats. Bullets larger than the cylinder throats will be sized/swaged down as they pass through the throats (if too large some lead spray will show up on the cylinder face or forcing cone/frame). If the bullets are smaller than throat size more than likely barrel leading will occur. Some rely on obturation (bumping up) for bullet fit, but that largely depends on bullet alloy and powder charge. K.I.S.S.; make sure the cylinder throats are larger than the groove diameter of the barrel and your cast bullets are the same diameter as the throat. Ninety-eight percent of the time this will solve your leading problems...

It's a lot easier than it sounds and has worked for me shooting lead free in 7 revolvers, and you only gotta do it once...

 

[Mus408]

"Drop through", "push through", snug, loose whatever, are not measurements. I prefer to know the diameter of my revolver throats so I either use pin/plug gauges, ball gauges, and I have slugged cylinder throats (prolly the easiest). For the best starting point, size or purchase your cast bullets the same diameter as the cylinder throats. While you're slugging, slug the barrel to make sure the groove diameter is smaller than the throats. Bullets larger than the cylinder throats will be sized/swaged down as they pass through the throats (if too large some lead spray will show up on the cylinder face or forcing cone/frame). If the bullets are smaller than throat size more than likely barrel leading will occur. Some rely on obturation (bumping up) for bullet fit, but that largely depends on bullet alloy and powder charge. K.I.S.S.; make sure the cylinder throats are larger than the groove diameter of the barrel and your cast bullets are the same diameter as the throat. Ninety-eight percent of the time this will solve your leading problems...

It's a lot easier than it sounds and has worked for me shooting lead free in 7 revolvers, and you only gotta do it once...

I measure everything with mics, hole gages, and pins. Just put that in there how the bullet fit was.

 

[mikld]

"Drop through", "push through", snug, loose whatever, are not measurements. I prefer to know the diameter of my revolver throats so I either use pin/plug gauges, ball gauges, and I have slugged cylinder throats (prolly the easiest). For the best starting point, size or purchase your cast bullets the same diameter as the cylinder throats. While you're slugging, slug the barrel to make sure the groove diameter is smaller than the throats. Bullets larger than the cylinder throats will be sized/swaged down as they pass through the throats (if too large some lead spray will show up on the cylinder face or forcing cone/frame). If the bullets are smaller than throat size more than likely barrel leading will occur. Some rely on obturation (bumping up) for bullet fit, but that largely depends on bullet alloy and powder charge. K.I.S.S.; make sure the cylinder throats are larger than the groove diameter of the barrel and your cast bullets are the same diameter as the throat. Ninety-eight percent of the time this will solve your leading problems...

It's a lot easier than it sounds and has worked for me shooting lead free in 7 revolvers, and you only gotta do it once...

I measure everything with mics, hole gages, and pins. Just put that in there how the bullet fit was.

OK, you know what the "real" dimensions are of your bullets and your guns. Just wondering, why the "slip fit" test reference? Were you asking why some want a questionable/sloppy bullet to gun fit? You're not getting any leading so all is well...

 

[LAH]

I use pin gauges on the cylinder. I slug the barrel. But to answer you question I drop a bullet in the cylinder & if I can push it through with a dowel I call it good. If it falls through I look for something larger.

 

[hdrk1111]

What if they drop in to almost the bottom then hang up and require quite a good tap to push them through ?

 

[LAH]

They should drop through the chamber & stop in the throat. Personally if I have to tap them through I size them a little smaller.

 

[hdrk1111]

I know this my seem a newb question and it is, but is the throat in the cylinder just at the very end befor they actually enter the forcing cone ?

 

[LAH]

In simple terms...........yes.

 

[hdrk1111]

Thanks LAH I appreciate the help.

Bob

 

[LAH]

You're welcome Bob.