Either a great idea or a waste of my good money...

[Elkins45]

So I learned this weekend that a letter 'N' size drill measures about 0.302 inches. That's just about the perfect diameter for a smooth side paper patch boolit to shoot in .30 caliber rifles.

So here's the plan: the next time I order reloading stuff I'm going to pick up a Lee 7mm rifle mold. Then I'm going to clamp the blocks together and drill the cavities almost to the nose with a N bit. Hopefully I can get a decent transition at the nose with the existing cavity. Then I'll cast some up, patch them and let 'em fly!

That's the plan anyway...a poor man's PP .30 cal boolit. Anybody like this idea better than just casting .309's and squeezing them unmercifully after they have been patched?

Comments welcome!

[waksupi]

It being hard to drill a nice, clean hole, I believe I would go down in either number, or letter drills a few thousandths, and polish the final few thousandths. Practice on some scrap metal, before trashing a mold.

[longbow]

+1 for what waksupi says.

The route I took was to buy an N reamer, drill undersize just as waksupi said then ream to final size with the N reamer.

I used a simple pushout mould design rather than split blocks but the size is good. Lyman recommended 0.301" for their PP boolits but 0.001" is nothing to worry about, just choose paper accordingly.

Longbow

[mooman76]

I also agree. I am no machinest but have done sme minor work. The Lee moulds are very soft aluminum. You also might want to see if someone here has a trashed mould you can use.

[Mk42gunner]

I read of someone using a D reamer to make a .35 cal PP boolit, that sounds easier to me than trying to drill a perfectly round hole.


Robert

[Elkins45]

+1 for what waksupi says.

The route I took was to buy an N reamer, drill undersize just as waksupi said then ream to final size with the N reamer.

I used a simple pushout mould design rather than split blocks but the size is good. Lyman recommended 0.301" for their PP boolits but 0.001" is nothing to worry about, just choose paper accordingly.

Longbow

Any suggestions where a fellow should buy an N reamer? I have an N bit but I don't have any reamers.

[izzyjoe]

you must have espn , cause i was thinkin' the very same thing,but for 8mm. i'm going to use a crapped out .30 mould i have. if you take you'r time cut slow and use cuttin' oil you'll be ok.

[garandsrus]

Here's a "N" reamer for about $15.

http://www1.mscdirect.com/CGI/NNSRIT...MT4NO=84450355

Here's one on eBay at about $15 shipped: http://cgi.ebay.com/Letter-N-Carbide...item27abb629d1

John

[chboats]

Elkins45
PM sent

Carl

[longbow]

I can't remember where I bought my N reamer other than in Canada. I was living in Kemano in Northern coastal BC just below the Alaska panhandle at the time so I must have ordered it or maybe the Alcan warehouse brought it in for me. We couldn't get out to shop much.

Nowadays, I just make a D bit the proper size from a grade 8 bolt or medium to high carbon steel. Mazda MPV headbolts work great and it is the best use they have been to me (a whole other story but I won't buy a Mazda again!). I even made the mistake once of using to low a carbon steel and could not get the hardness so case hardened and that worked fine too.

I use these to make mild steel and bronze moulds and they work just fine so there would be no problem with aluminum.

Longbow

[Slow Elk 45/70]

OK if you are aperson with a lot of machinist knowledge, and a drill press and lathe, have fun what ever you do...m

[Dollar Bill]

It being hard to drill a nice, clean hole, I believe I would go down in either number, or letter drills a few thousandths, and polish the final few thousandths. Practice on some scrap metal, before trashing a mold.

++!.
Drill bits made to the NAS 907 standard typically measure .001 to .0025 below there stated size. The finished hole, assuming a proper set-up, has a +.005 / -.001 tolerance, depending on material. Aluminum's harder to hold tolerance on than, say 4130 steel. Reamers hold a tolerance half that, maybe more, depending on the reamer quality, set-up, lubricant used, etc.

[KYCaster]

Here's a place in Louisville that probably has what you want......

http://www.higginsindustrial.com/index.html


Good luck

Jerry