GC mould bored out to plainbase

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  • Last Post 10 March 2009
Ed Harris posted this 15 January 2009

I inherited a 4-cavity NEI mould .308-142GC in which the GC heel was oversized, so that Hornady GCs would not seat fully, and the length of the GC heel was too short, so that even if you did chamfer the bullet bases with a deburring tool, and anneal the GCs so that they could be carefully seated, the GC would impinge against the rear band.  On top of that the rear driving band cast undersized and I never got the bullet to shoot very well. 

However, the forepart of the bullet was nicely tapered and fit the throats of my Springfield and Mauser .30-'06 rifles well.  So I approached Erik Ohlen at http://www.hollowpointbullet.com>http://www.hollowpointbullet.com about boring out the GC heel and enlarging the base band, to produce a 150-gr. plinker for .30-'06 gallery loads.

The resulting modified mould fills out and drops much easier. It has a .311 base band.  When seating the base band only in the .30-'06 the top driving band engaves nicely in my 03A3 when you close the bolt, but it extracts without de-bulleting.

I've loaded up a bunch of these with 7 grains of Bullseye and will try them in near-zero weather in West Virginia this weekend.  What could be better than “a real New Hampshire Day” to try out a new load.  Frank Marshall would approve.  Stay tuned...

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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CB posted this 17 January 2009

God love ya Ed! That looks like it would be a blast! Boy I tell ya, I was out for a bit today with the boys, we were supposed to have a poker shoot. The wind was blowin and the snow was coming down, I managed to fire 10 rounds out of the 1911.. It was miserable. But... The fire in the hut was warm and the conversation enlightening.. What a grand day it was!

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Ed Harris posted this 22 January 2009

Got in several good range days in West Virginia, took the Coleman stove to the range so we had a coffee pot and kettle of clam chowder going whenever we needed to warm up. Monday temperature was 7 degs. F. with wind chill below zero and cold batteries wouldn't power up the chronograph so we did't stay very long, just plinked the steel gong with the bunny guns.

Took three of the best digital camera clips of the bunny guns in action and zipped them up here: http://hgmould.gunloads.com/a/bunny.zip>http://hgmould.gunloads.com/a/bunny.zip

If you click the link you will get a “Save as” window for the zip file download.

Tuesday Inauguration day warmed into the mid 20s and wasn;t too bead if you were properly layered up. Walmart has snowmobile suits up to 4XL. The new 152-gr. NEI plainbase as modified shoots well in the 03A3 with 7 grs. of Bullseye. Need to try it in the Krag next time.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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KenK posted this 25 January 2009

Ed, what are some commonly available 30 caliber moulds that you think might be particularly suitable for converting to plain base?

Something in the 170-200 grain range for the .308 or 30/06.

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Ed Harris posted this 09 March 2009

KenK wrote: Ed, what are some commonly available 30 caliber moulds that you think might be particularly suitable for converting to plain base?

Something in the 170-200 grain range for the .308 or 30/06.

Any undersized mould or one with a botched GC heel. Don't purposefully modify a mould which shot well either with a GC or without one, just for the shear heck of it. 

If I wanted a plainbased bullet in the weight range you speak of and had a #311466, #311291 or RCBS 30-150FN block I wasn't using much, or anything which cast undersized needed a larger base band, those would be candidates.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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CB posted this 09 March 2009

There have been several posts in this thread and elsewhere about boring out a gas check mold to make it plain base.  The conventional wisdom used to be that a gas check bullet could be shot without the check and get similar results to a plain base bullet of similar design.  I think Col. Harrison and others of that era may have said such things although I can't remember and am too lazy to look up.

Of course CW is often a bunch of poppy cock repeated enough times.

I can see that boring out the gas check shank would increase the length of the base band and increase the overall length of bullet bearing on grooves.  What are the other advantages.  Does it improve accuracy over just shooting them plain based but with the gas check shank still on?

If the consensus is that it helps, is this based on testing or just an opinion based on what seems like it makes sense?

John

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KenK posted this 09 March 2009

I have had reasonably good results shooting gas check bullets without the check.  I'm waiting on three moulds to come back from the hollow point man now with the shanks bored out.

My primary reasons for having them altered is the hope that they might shoot better and a dislike for dealing with the excess lube that fills the unused shank.  It is a PITA to wipe it off before seating the bullet and if you don't it soon gunks up the seating die.  Not a problem for those that tumble lube I suppose.

I will post some before and after results when I have them.

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CB posted this 09 March 2009

Has anyone had problems with the wide base band? I've milled the check shank off a couple of moulds but never tried boring one out.

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linoww posted this 09 March 2009

If it stays above the sized area of the neck it works fine.(i am assuming using bullets sized in a die the same width as the band or pan lubed)But when is goes below you end up having too loose neck tension like when you size .310 GC bullets in a .313 die and it expands as it seats,but once it is below the neck tension is too loose for the bullet body.

I think over sized bands work very well in plainbase loads.As long as it isn't .317 or something crazy.

George

"if it was easy we'd let women do it" don't tell my wife I said that!

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CB posted this 09 March 2009

George, I was thinking more of the width of the band than the diameter.

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linoww posted this 09 March 2009

The ones i have had done work well,but the baseband is pretty thick.I  just had a 311284 done and i'll post pictures when i get it back.it was a beater mold that cast very round that someone filled an index mark in with a freaking chainsaw file!! (its like “you know who” owned the mold<G>)I had the guy at HP molds tig weld it in and also make it a plainbase.

George

"if it was easy we'd let women do it" don't tell my wife I said that!

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redball2 posted this 09 March 2009

I have shot quite a few gas check design bullets without the gas check and they always work ok. I never wipe the lube off the gascheck base, unless it's real hot it doesn't cause any trouble. just don't try to shoot them more than 1100 f/s. although today I was experminting with a light cz 547 223 and bullets out of a nei mould that jess miller gave me. one is the 70 grain and the other is suppose to be about 50 grns. at 50 yards they stayed in an inch with 5 grains of bulles eye. At one time I used  the lee 312-160-1r and a lite charge of unique at 50 yards in a heavy barrel '06 to get the feel of the gun for a 1000 yd match with the same sight settings for a 1000 yds of course it printed about 2 ft high at 50 yds but it was accurate enough to teach me some things about the rifle. the only way you will know if it will work is to try it.

Jim wilcox

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Ed Harris posted this 10 March 2009

In my case boring out was done to salvage a botched mould. In most cases the GC type bullet shot without a GC works better than the plainbase. I did it for bullet fit and because it was cheaper than buy a new mould which might also be botched, if it was a tooling mistake.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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