78gn LeHigh Close Quarter Bullet

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rebel
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Re: 78gn LeHigh Close Quarter Bullet

Post by rebel »

The loaded ammo I shot was out of a 1 in 8 9" and no issues.
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gds
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Re: 78gn LeHigh Close Quarter Bullet

Post by gds »

JD_H wrote:i mention 223 and get berated :roll:
No that would not be the case at all.

You were berated for being a less then pleasant individual with a know it all attitude, and after having the reasons explained to you why klem, who happens to be a great contributor to this forum, chose to try this bullet, you decided to continue on with your less then pleasant persona.

That you think it was because you mentioned the 223 shows that you have a serious inflated opinion of yourself and an inflated opinion of the value of your opinion.

But thanks for contributing.
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Re: 78gn LeHigh Close Quarter Bullet

Post by Klem »

JD_H wrote:love tha warm welcome to the forum! :lol:
Welcome to the forum.

Like any social group the forum has etiquette and you put your foot in it from the start. You weighed-in with no experience on a very specific topic and then attempted to hijack the thread. More specifically your comment that I shoot .223 was confrontational. No sense in pleading hurt and innocent as we all know it was designed to provoke a response....and you got one.

My advice is to STFU and start your own thread. If you are interested in philosophical debates about this calibre then you can chit-chat away from the proprietary position of owning your own thread. First check that it is in the correct part of the forum (Forum Index).

Sometimes it's better to listen than talk.

I apologise to everyone for getting riled-up, this is not how I prefer to contribute. My thanks to everyone for helping me on this, I appreciate it.
Last edited by Klem on Sat Jan 02, 2016 11:30 pm, edited 1 time in total.
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dellet
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Re: 78gn LeHigh Close Quarter Bullet

Post by dellet »

I went back through all my notes on this bullet and the emails with Lehigh.

Basically the bullets stayed together with 19gr of #9, but at distances past 50 yards holes were no longer round and groups opened up significantly. An inch at 50 become 6" 100. I assumed this was due to the bullets starting to come apart. Faster powders they came apart immediately.

When you look at the original threads Lehigh was saying 3000fps in a 1/8 twist, when they published data it was less than 2800fps. I would guess max bullet RPM will be somewhere in that range.

The numbers I ran at the time:
1/8 twist @ 3000, 270,000 rpm
1/8 twist @ 2750, 245,000 rpm
1/7 twist @ 2750, 283,000 rpm
1/7 twist @ 2500, 257,000 rpm
1/10 twist @ 2750, 198,000 rpm
1/10 twist @ 3600, 259,000 rpm

The next loads I had wanted to try using #9 were to start at 16gr and work up to velocity/rpm in that 2500+/260-270,000 area. I think 275,000 might be about max

The other test load was using Lil'gun, 20 grains should reach 2700 fps, but it had the lowest pressure and longest time to peak pressure at that velocity. Hoping this would test the rapid acceleration theory.

This thread has renewed interest in the bullet, so I'll try to do some of this in the next couple weeks. Hopefully some of that will help others.
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Re: 78gn LeHigh Close Quarter Bullet

Post by Klem »

Interesting...

I calculate my RPM was 253,440 so might have been more to do with acceleration as opposed to RPM.

AP100 is the slowest of ADI's pistol powders (AP = 'Australian Pistol'). Usually there is a Hodgdon equivalent but none for AP100. Burn rate equivalents to AP100 found here;
http://www.adi-powders.com.au/handloade ... alents.asp

You can see it is a pretty fast accelerating powder for this calibre but the Quickload (QL) simulation had it being the most efficient. Moot point now given it came apart and also does not produce enough gas to cycle.

Your 20gns of LilGun shows 112% case capacity on QL so a fairly decent compressed load.

I know someone with an old M1A. 22" barrel with 1:11 twist looks like about 3,700fps on QL and 242,000rpm. Miller Formula (JBM online) displays this as '1.8 stable'.
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Re: 78gn LeHigh Close Quarter Bullet

Post by dellet »

Sometimes I cheat on loads :shock:

I do all of my testing like this is in a bolt action, so I can just neck size a case for max capacity, then work it back down. This adds almost a full grain of capacity and greatly reduces pressure. Drops calculated density to 110% on this load, still up there.

I actually shot one tonight and no signs of pressure, bullet held together, so will try a few tomorrow if time permits. It was after dark, so not velocity.


I also ran the numbers and think I can sort out twist vs velocity. I can run that same load in a 7" 1/6 twist. It estimates at around 2200fps and 265,000 rpm.

One more piece of the puzzle was that I noted never having a problem with first round, but as I shot more rounds, the problem was more likely to happen.
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Re: 78gn LeHigh Close Quarter Bullet

Post by 1slow01Z71 »

Why would you want to run a 6 twist in a 7"?
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dellet
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Re: 78gn LeHigh Close Quarter Bullet

Post by dellet »

1slow01Z71 wrote:Why would you want to run a 6 twist in a 7"?
Basically it will stabilize anything at any velocity I can run though it. For supers many bullets will not reach their potential bc if they spin too slow and you lose enough velocity in that short of a barrel so anything helps.

There is also an argument that getting less than one full revolution in the barrel can diminish accuracy. That requires about 7.3" of barrel with a 1/6.

The 7.5" barrel I had was very accurate across the weights and velocities I tried, I was asked if I wanted to try the 7" to compare so here I am. So far I have not noticed a difference, but I only have about 25 rounds through it.
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Re: 78gn LeHigh Close Quarter Bullet

Post by plant.one »

Klem wrote:Interesting...
Your 20gns of LilGun shows 112% case capacity on QL so a fairly decent compressed load.
according to nosler's 7th, 20gr of lil gun under a 110 varmageddon @ 2.025" is at 110% of case volume - with nosler brass.

i've shot that same load in hornady and LC brass and shown no pressure signs with it (primers looked about like the one dellet showed, maybe a bit flatter, but still nicely rounded corners) - in fact, that happens to be my accuracy load (in LC brass w/ cci 400's @2248 fps)

so while i've never played with the Leigh stuff i wouldn't be terribly shocked that being in the 110-112% case volume compressed would perform just as well with this bullet. lil gun seems to be happy when it goes *crunch* as you seat the bullet
Reloading info shared is based on experiences w/ my guns. Be safe and work up your loads from published data. Web data may not be accurate/safe.
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dellet
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Re: 78gn LeHigh Close Quarter Bullet

Post by dellet »

No velocity measured and only ran these in a short barrel with a 1/6 twist. I will run them again when I can, in a longer barrel for higher velocity and at a greater distance to see if they are staying intact. For now I am really leaning toward to fast of powder as being the problem before.

Target backing is 22"x28" poster board, no petals lost, nice round holes.

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