Removing Gas Check Grooves

[Green Frog]

There have been several mentions here about modifying factory moulds that came with gas check grooves so they would cast plain base bullets. I’ve known a couple of machinists in the past who did this kind of work, but they are gone now, and this kind of work is above my pay grade in the shop. Does anyone know of a machinist who still might offer this service? I’m specifically thinking of having my double cavity Lyman 358156 altered since I shoot these bullets with naked bases most of the time anyway.

TIA ~ Froggie

[Outpost75]

I've had Erik at www.hollowpointmold.com enlarge the GC heel or entirely remove it, either by boring it out to make a heavier bullet of larger diameter, or by shortening the blocks to make a lighter bullet.

[MT Gianni]

NOE sells a pb 156. I have done some on a drill press with minimal run out and a good machinist vise. This was and is just for my own use. The hardest part for me was determining if the cavity is parallel to the mold edges. If you do err and get a larger base the sizing die can fix most of it. My criteria was being cheap and having an easily replaced mold.

[gwpercle]

Never pass up an excuse to buy a new mould .
Keep the 358156 GC ...you will want to load some 357 magnum loads some day...trust me.
Gary

[NoZombies]

I've had Erik at www.hollowpointmold.com enlarge the GC heel or entirely remove it, either by boring it out to make a heavier bullet of larger diameter, or by shortening the blocks to make a lighter bullet.

I second this, Erik isn't cheap, but his work is worth the price.

[longbow]

You can buy reamers from McMaster Carr in readily available sizes at 0.357", 0.3575", 0.358", 0.3585", 0.359", 0.3594", 0.3595", 0.360" for about $15 to $30 and use a drill press then hand turn to remove a gas check shank.

Ben has posted info on moulds he removed gas check shanks from that way using just a standard twist drill.

Its not that hard to do if you want to do it or get it done but... as stated above, maybe a new PB mould is a better route?

[Green Frog]

Thanks guys, you've given me a couple of viable options here. I didn't know about the NOE mould... a nice DC brass in a 358156 PB might be my best bet since I've fallen in love with brass moulds too. I'm still not too hep on doing it myself, but if NOE doesn't pan out, Eric will be a good option. Thanks again my friends.

Froggie

[Green Frog]

NOE sells a pb 156. I have done some on a drill press with minimal run out and a good machinist vise. This was and is just for my own use. The hardest part for me was determining if the cavity is parallel to the mold edges. If you do err and get a larger base the sizing die can fix most of it. My criteria was being cheap and having an easily replaced mold.

I spent the better part of an hour perusing Al’s site last night and never did figure out which of his mould number is the equivalent of the ideal 357156. I saw a couple that seemed close, but none I found was an exact match. Do you have a Mould Number you could give me, please?

TIA ~ Froggie

[MT Gianni]

https://noebulletmolds.com/site/product-category/358/360-165-swc-t5
When I ordered mine 5 years ago or so this weighed in at 158. Dimensionaly it looks similar but I sure can't see a 156 in there now. Sorry, I should have looked before posting.

[Green Frog]

Thanks, MG. That looks like it may be the one. Additionally, unsized bullets from this mould should be perfect for my little 38 S&W Terrier. Al seems to be sold out of all the variants I would be interested in buying, but I’m in no hurry. A solid point plain base version of this in a 2 cavity brass mould is now officially on my wish list! :mrgreen:

Of course a spare double cav Lyman 358156 would still be in danger of being altered at my house. ;)

Froggie