Went to test reload today.  Trying to get a multi gun load for Kimber 1911 and New HK45.  I previously was using Montana Gold 230 JHP, 3.9g, CCI primer, and 1.205 OAL.  On Kimber 1911, it shoots soft with no problem.  On HK45, it will jam every two rounds.  So I decided that it might be the bullet head.  I switch to Montana Gold 230 CMJ, bump to Clay 4.2g, CCI primer, and 1.23 OAL.  Test 20 rounds.  Kimber shoots great with no problem.  On HK45, it jams every two rounds.  Test another 20 rounds.   Bump to 4.3g and same OAL.  Kimber shoots even better with no problem. On HK45 all round shot ejected without a jam, however at the last shot the slide will not lock back when empty.  I'm worried due to bumping up with the Clay powder at above recommended 4.0 for .45ACP will cause problems to the guns.  Should I just use stop with the Clays and try a different powder or bump the Clays to 4.4g and not to exceed 4.5g.

Went to test reload today.  Trying to get a multi gun load for Kimber 1911 and New HK45.  I previously was using Mountain Gold 230 JHP, 3.9g, CCI primer, and 1.205 OAL.  On Kimber 1911, it shoots soft with no problem.  On HK45, it will jam every two rounds.  So I decided that it might be the bullet head.  I switch to Mountain Gold 230 CMJ, bump to Clay 4.2g, CCI primer, and 1.23 OAL.  Test 20 rounds.  Kimber shoots great with no problem.  On HK45, it jams every two rounds.  Test another 20 rounds.   Bump to 4.3g and same OAL.  Kimber shoots even better with no problem. On HK45 all round shot ejected without a jam, however at the last shot the slide will not lock back when empty.  I'm worried due to bumping up with the Clay powder at above recommended 4.0 for .45ACP will cause problems to the guns.  Should I just use stop with the Clays and try a different powder or bump the Clays to 4.4g and not to exceed 4.5g.

Seems to be an oal and recoil spring issue. If u want to have a round that will shoot in both pistols u might need to play with the oal, may need to load longer and try and get a lighter recoil spring for the HK so that the pistol will operate with the lighter load I would advise not to exceed recommended max powder charge as it will definitely cause excessive wear and possible damage to the pistol. If all else fails u might need to get a slower burning powder than clays.

Went to test reload today.  Trying to get a multi gun load for Kimber 1911 and New HK45.  I previously was using Mountain Gold 230 JHP, 3.9g, CCI primer, and 1.205 OAL.  On Kimber 1911, it shoots soft with no problem.  On HK45, it will jam every two rounds.  So I decided that it might be the bullet head.  I switch to Mountain Gold 230 CMJ, bump to Clay 4.2g, CCI primer, and 1.23 OAL.  Test 20 rounds.  Kimber shoots great with no problem.  On HK45, it jams every two rounds.  Test another 20 rounds.   Bump to 4.3g and same OAL.  Kimber shoots even better with no problem. On HK45 all round shot ejected without a jam, however at the last shot the slide will not lock back when empty.  I'm worried due to bumping up with the Clay powder at above recommended 4.0 for .45ACP will cause problems to the guns.  Should I just use stop with the Clays and try a different powder or bump the Clays to 4.4g and not to exceed 4.5g.

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1-First of all, are you talking about MONTANA GOLD bullets?
2- Can you describe in detail the type of jam you are experiencing?
3- Did the HK run ok with factory ball (230 fmj) ammo?
4- Remove the bbl=>do the rounds fall in and out and headspace ok?
5- what dies are you using in your 450?
6- Are you taper crimping separate from seating? (using a fourth die station)
7- what is the final diameter of the case mouth?
8- What other powder do you have available?

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1-First of all, are you talking about MONTANA GOLD bullets?
2- Can you describe in detail the type of jam you are experiencing?
3- Did the HK run ok with factory ball (230 fmj) ammo?
4- Remove the bbl=>do the rounds fall in and out and headspace ok?
5- what dies are you using in your 450?
6- Are you taper crimping separate from seating? (using a fourth die station)
7- what is the final diameter of the case mouth?
8- What other powder do you have available?

1. Good catch.  Montana Gold
2. Jam is failure to eject.  Had no problem feeding.
3.  HK run great with factory Olin Match 230
4.  Round fall in and out.  Headspace ok. 
5.  Using Dillon 550 and Dillon Die.
6.  Dillon Crimp Die - should I get Lees factory Crimp Die
7.  Check diameter of the finished case mouth and is .467
8.  I have Red Dot for shotgun, H4895 for 308 win, H335 for .223 rem, and Clays for 9mm and 45acp

Should I try Universal Clays or Bullseye for  45ACP and 9mm?  and get Lees factory Crimp.  At this time been researching, HK does not carry light spring only stock.

+1 with check your oal
I would try different powder as well
Also +1 for lighter recoil spring for da HK

1. Good catch.  Montana Gold
2. Jam is failure to eject.  Had no problem feeding.
3.  HK run great with factory Olin Match 230
4.  Round fall in and out.  Headspace ok. 
5.  Using Dillon 550 and Dillon Die.
6.  Dillon Crimp Die - should I get Lees factory Crimp Die
7.  Check diameter of the finished case mouth and is .467
8.  I have Red Dot for shotgun, H4895 for 308 win, H335 for .223 rem, and Clays for 9mm and 45acp

Should I try Universal Clays or Bullseye for  45ACP and 9mm?  and get Lees factory Crimp.  At this time been researching, HK does not carry light spring only stock.

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1-ok
2-good, that is what I thought you meant
3-good
4-good
5-OH you got a 550? You told me you had a 450 a few months ago. No matter.
6-Dillon dies are fine. I use them
7- I would run the crimp at 0.465
8- Switch to RED DOT and run 5.3 gr. This will give you something like service ammo.
Note: Since the guns are feeding ok, leave the OAL's the same.

Not surprised that the HK is calibrated for service level ammo. It is also probably new and tight.
I would retain the stock spring, even if there were lighter aftermarket parts available.
You paid for a well designed HK, don't mess around with it.

I recently upgrade to 550. I will switch to powder for .45 acp. Keep Clays for 9mm.

I don't know what kind of power these cartridges would be since I'm not familiar with the powder, however I would put this out.

The power may not be enough overall to cycle the HK and this may not be apparent until the last round of the magazine.  If power is OK, then the HK may be suffering from a magazine issue.

One last thing.  What # recoil spring are you running on your 1911?  Is it at least 16 - 17 #?

1911 recoil spring I changed to Wilson Combat #18 and took out the recoil buffer.  I got a #22 but fell too stiff.  1911 runs great for now.

1911 recoil spring I changed to Wilson Combat #18 and took out the recoil buffer.  I got a #22 but fell too stiff.  1911 runs great for now.

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Put in a "shok-buff"
That little blue or black rubber thingy on the recoil spring guide.

I would not use a shock buff.  Certain guns do not have enough tolerance to use that and also fully cycle the slide.

I would not use a shock buff.  Certain guns do not have enough tolerance to use that and also fully cycle the slide.

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I know what you mean. But if the gun can function ok with a shok-buff then I would use it.
I do have colt 1911 with a cracked frame that might have been saved by the shok-buff.
The gun has many thousands of rounds through it. Mostly all full power IPSC major loads.