measuring land diameter

[wmitty]

I'm trying to shoot the .30-180 rcbs silleuette (sp.?) in a 788 Rem. chambered for the .30-30. I'm using HTWW and the bore rider portion of the bullets are running about .3025"and are difficult to chamber and extract if unfired. I've already managed to break the extractor trying to remove an oversize case ( went too long before F.L. resizing brass) so I'm interested in nose sizing the bullets to land diameter. What's the correct way to measure land diameter? Should I have a die made to whatever the land dia. is or slightly larger? Any help appreciated!

[9.3X62AL]

Very limited experience with this particular gymnastics routine, but here goes. In my Ruger #1 x 45-70, I had some similar experiences with a couple bore-rider boolits, so I had my close Burrito Associate Senor Buckshot assist with his pin gauge set. He used this in kind of a "go/no-go" fashion, and the reading was .449" land height. Since the boolits were .451" on the nose, that answered the question.

I pondered how to proceed to make these boolits usable, and messed around a little with the sizer die. Those long bore rider portions DO bump up a little when sizing the drive bands, so my thoughts were to do the nose portion AFTER sizing and lubing the drive band portion of the boolit--if the nose was too large for the lands. The back edge of this sword is that a too-small bore rider might get bumped up a bit when sizing/lubing the drive bands, and possibly in the nose sizer as well. Any bump-up of the drive bands during the trip through the nose sizer won't hurt a thing, as long as the resulting loaded round will chamber safely and release the boolit at firing without egregious pressure build-up.

I'm half-way to the resolution of this problem currently--I had Buckshot make up some top punches that could accomodate the boolit bases in three sizes, and have yet to speak to him about the nose sizer. Varying alloys likely have varying "spring-back" after sizing, a characteristic that can both complicate the die maker's job and conversely be manipulated by the end user to vary final diameter. One other factor to consider is that a 2nd trip through the sizer die provides a 2nd oppurtunity to bend the boolit, which is the rationale behind the boolit base top punch idea--to get as much straight-line alignment at the start as possible.

I'm guessing that others have "seen this movie", and I would like to hear their comments before I hit Buckshot up to make the die.

[44man]

The easiest way is with a small hole gage. You expand it for a nice fit and measure it.
Do you see land marks on the nose of an extracted boolit?

[Bass Ackward]

I'm trying to shoot the .30-180 rcbs silleuette (sp.?) in a 788 Rem. chambered for the .30-30. I'm using HTWW and the bore rider portion of the bullets are running about .3025"and are difficult to chamber and extract if unfired. I've already managed to break the extractor trying to remove an oversize case ( went too long before F.L. resizing brass) so I'm interested in nose sizing the bullets to land diameter. What's the correct way to measure land diameter? Should I have a die made to whatever the land dia. is or slightly larger? Any help appreciated!


Mr. Mitty,

Take one and try it from the muzzle end. It is quite posible that the nose .... isn't the problem. You might have a tight neck and the size of your bullet in general may need to come down or your brass might need reamed / turned / trimmed.

If so, before I went the extra expense and time with another sizing option / operation, I would do two things.

First I would run a patch up in the throat and leave it set with some strong ammonia on it and see if there is any copper left at all. If not, I would mix my WW 50/50 with pure lead and then water drop those. You will lose at least .0005 on the nose and the slightly softer bullet 16-20 BHN should be easier to engrave. Especially if you use some LQA on the nose for lubrication.

If this gun has not been a cast launcher in the past, you will experience some loss of land height and lengthening of the throat after about 200 rounds of hard lead. Especially if you .... push it. Once this happens, you may in fact appreciate the extra nose diameter at that time. Then if your sizer was made to deal with today's measurements, you could be undersized at the .... break-in time.

Personally, I would endure the pain and shoot it. Many people would dearly love to have your problem to include me. It won't hurt anything to bang that baby into submission. :grin:

One last option is to trade your mold with someone that needs the larger nose. Some people would kill for that mold.

[wmitty]

Engraving from the lands is very obvious on the bore riding portion of the nose on these bullets. I am trying to shoot the bullets " as cast " by running them thru a Lee .311" die simply to seat the gas check. It just dawned on me that a lubrisizer would be required for the nose sizing operation ( I don't own one) unless a nose punch was made up to drive the partially sized bullet from a Lee type sizing die.
I guess the simple solution is to change alloy content as Bass recommended 'til the nose is small enough to allow easy chambering of the cartridge. Thanks for the idea!