Issue (?) with the discontinued RCBS 180 SPGC (Mould ID 82020)

I just bought an FN commercial sporter (98 pattern) and slugged the bore. I have the discontinued RCBS 82020 (180 SPGC) mould which has a long nose section that measures .304. My groove diameter is .3095 and I intend to start out sizing them .310.
The diameter across the lands is smaller than the .304 nose so I will have to seat these bullets quite deeply in order for the round to chamber as the nose is not small enough to "ride" inside the tops of the lands. Is this customary? I am assuming it is and that there is no harm when there is a significant portion of the bulled that is deeper than the shoulder/neck junction.
I don't know what my diameter is across the tops of the lands but I suspect it is in the .290-.300 range. A cast bullet nose doesn't come close when I try to start it in the muzzle just as a test. I'm not sure these dimensions are going to let the bullet's full diameter fall under the neck of the case. I am waiting on components so I haven't made up any dummy rounds yet to confirm this.
I've just never cast for rifles before and the above issue obviously never came up in the thirty years I've been casting for revolvers.
I searched this forum and I did find a few shooters who have experience with this bullet. I'm hoping they are still around.
Thanks everyone.
Ed

I'd try them first. The design might surprise you.

Rifling making marks on the nose is common, and some say it helps.
Do a little search for 'bore riders'. It'll take you to archives on a few forums where they are discussed.
That mold's bullet may just be a bore rider.

For starters, I'd seat to the normal OAL.
Chambering a dummy will tell you a lot.
You'll feel the resistance if the nose gets marked a large amount by the rifling.
Boolits are so soft, with a few short, shallow rifling marks,
they don't make a serious bore obstruction like a jacketed bullet does.

I have that mould design I believe. It’s the rcbs Spitzer 180 grain gas check with the bore rider ogive and very small meplat. If you have a bore diameter that is preventing the boolit from being seated with the gas check at least flush with the case neck/ shoulder junction, you might consider having the throat reamed deeper. I’m surprised your land height would be less than .300” but if the boolit is being forced below the neck/ shoulder in order to chamber sounds like this might be the case. I have had excellent accuracy with this design and the M 700 barrel’s .301/.308” land and groove dimensions. I’ll measure the bore riding portion if I still have some of these cast and waiting to be loaded.

Quote:

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Originally Posted by wmitty

I have that mould design I believe. It’s the rcbs Spitzer 180 grain gas check with the bore rider ogive and very small meplat. If you have a bore diameter that is preventing the boolit from being seated with the gas check at least flush with the case neck/ shoulder junction, you might consider having the throat reamed deeper. I’m surprised your land height would be less than .300” but if the boolit is being forced below the neck/ shoulder in order to chamber sounds like this might be the case. I have had excellent accuracy with this design and the M 700 barrel’s .301/.308” land and groove dimensions. I’ll measure the bore riding portion if I still have some of these cast and waiting to be loaded.

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I can't imagine even with the softest alloy (I'm using #2 BTW) that a .304 nose is going to go in a (likely) .301'ish barrel but I cast up some so may as well try. If anyone wants to send me $60 I will ship it today CONUS. I'm not an experimenter as much as a shooter looking for economical practice with my deer rifle. I'm going to look for a more "user friendly" design for sale. I'm happy to swap for something you think is more appropriate to my needs.

I've had this mould for at least thirty years. I seldon use it anymore as I prefer a slightly heavier bullet, but the 180 has been an accurate bullet in several rifles. I don't recall ever measuring the nose diameter, but I'm sure it's not anywhere near .304". I've never had to seat that bullet below the case neck, though I'm not adverse to this practice. I've had good result with other bullets that had bases extending below necks. The similar 165 RCBS spitzer is another good bullet with simialr characteristics.

Longfellow: Before you do anything else, check to see if the mold blocks are closing completely. With your mold blocks in the mold handles, and the sprue plate open, close the mold blocks and then hold them up to the light. Do you see a line of light where the mold blocks meet? If so there's something preventing the mold from closing completely. It could be flecks of lead on the face of the mold blocks, dents around the edges of the holes for the alignment pins, or some other problem. If your bullets are casting with the nose too large in diameter, first check to see if the mold blocks aren't closing all the way. If they're not, post some pictures or describe the problem, and I'm sure that there will be people here with suggestions on how to fix the problem.

Also, if your bullets are too fat, you might still get them to chamber but they may not extract. Your Mauser will probably have enough camming force to push a cast bullet into the lands when you close the bolt. But (try this with a dummy round first) when you open the bolt and try to extract the dummy round the bullet may stay in the bore as the case is withdrawn. If that happens you can knock the bullet out with a range rod. If you try this with a live round it will dump powder all over inside the action and make a mess.

I have that bullet mould and think your mould blocks are not completely closing

I lapped mine out from a .299 nose to .301 / base from .3095 to .310

One of the bullets that I use in new barreled 308/ 3006

works great in m1 and m1a's with h & imr 4895 powder with a tuff of Dacron

Some of mine are a bit tight but if i can fish a loaded round fully chambered with only a finger nail on the rim i call it good

if it closes and leaves a bullet in the barrel its too big and not safe to use

311299 is also a good bullet and for those on the well used side 312299 or the 314299 for a very well used barrel

I’ll check roundness (mould not closing). Good tip.

Two bits of news. The bullets are perfectly round; at least as close as I can measure with a dial indicator on the nose with the base chucked and spinning in my lathe. So the mould is completely closed.
Second, I now have dies and everything needed so I made up some dummy rounds. With the bullet's base just barely entering in to the body of the case, that is to say the gas check bottom is about .100 inch below the base of the neck (the neck/shoulder juncture is a generous radius so I can't be more precise about this), I CAN chamber the round. There is definite engraving of the rifling on the bullet but probably not the full depth of the groove. Is this an acceptable situation with regard to safety? If it is, then I'll load up some light loads (10-12 gr Unique) and start testing. If any of this is unclear and you need better detail before commenting, please ask. Thanks.

Many suggest never seating a cast bullet w/ the GC below the neck / shoulder junction, but in my recent use of a tight bore 1941 vintage M99 300 Savage, it all worked out fine. Never had a check pop off in the bore by any overt signs, as some suggest they can when seated deep, and it shoots well (Lyman 311291).

I think what can happen easily (as seen from pulling bullets) is that powder can get into the lube grooves when they are exposed inside the case, and that may not be the most ideal thing.

Most bottleneck cartridges I use cast in don't need the bullets to be seated deep for my guns, but I don't think you should fear it either as long as the checks crimp on nicely. Just don't chamber and then pull a loaded round if the nose jams into the lands. As 405grain says in post #6: it makes a mess.
Ruined my day once 15 or so years ago when I had to go home to to dislodge the bullet and clean out the action. "Cease fire" meant NOW at the range I used to go to. No '..shoot your chambered round...' courtesy.

Well every little bit helps. I lightly stoned the edges as well as the mating surfaces just to see if there were any high spots that were keeping the mould from closing and I guess I did improve things some. The nose diameter now mics at .302 instead of .304 and this now is sufficiently close to the diameter across the lands to allow bullets to enter the rifling. I can even extract them without leaving them in the barrel so I think I'm going to be fine as I begin loading and shooting. Thanks all for your tips.