Chronos, load development and Recoil Springs

[Chapo]

Well, finally decided to go with 115gr everglades bullet over 10g of AA7 at 1.165."  This makes 169 PF and I'm comfortable with that.  Seems like the best for my Czechmate.  Next will load some and tune for recoil spring.

Edited April 5, 2023 by Chapo

[zzt]

1 hour ago, Chapo said:

zzt, which powder? AA7 or SWorld?  Also were you shooting a Czechmate?

 

At the time I was shooting SWMP powder.  AA7 now, because that was what I have now.  AA& and SWMP (Lovex 37.1) are the same powders.  Lovex is mfg. in  Czech., AA7 is mfg. here.  Lovex is not as consistent lot to lot,  so I switched to AA7.

 

I am not shooting a CM  Mine are custom 2011s.

[lroy]

2 hours ago, shred said:

The increased wear has little to do with recoil assuming a reasonable spring.  Maybe you'll sandblast the comp more with unburned powder grains.  That would happen in mucho-powder loads in the 9x25s; comps wouldn't last very long before you could drop .40s through them.  Not that big a deal.

 

The biggie is chamber pressure is trying to separate the slide and barrel.  More velocity = more pressure.  That leads to slide cracks.  I hate slide cracks.

 

Is pressure more a result of oal than powder charge? For example, if you had two cartridges at 9.5gr - one at 1.13 and the other at  1.18, the shorter would have far greater pressure while producing the same amount of gas to work the comp as the longer one?

[shred]

That's what interior ballisticians get paid the big bucks and have fancy labs to sort out.  There's a zillion variables from burn rate to granule size and composition and so on, but nearly always the same powder charge in a shorter OAL is going to have higher pressure.  The old VV powder flyers used to have some info on that but I think it was removed a decade or more ago because people were trying to get creative.

 

I still say chasing ultimate flatness is mostly a waste.  Back when we shot 9x25 Dillon there was enough powder volume that you could make loads that would have the dot recoil down or just sit there.  Turned out having 3 more rounds in a big-stick mag that you'd only use occasionally was far more valuable.

 

[caspian guy]

55 minutes ago, shred said:

That's what interior ballisticians get paid the big bucks and have fancy labs to sort out.  There's a zillion variables from burn rate to granule size and composition and so on, but nearly always the same powder charge in a shorter OAL is going to have higher pressure.  The old VV powder flyers used to have some info on that but I think it was removed a decade or more ago because people were trying to get creative.

 

I still say chasing ultimate flatness is mostly a waste.  Back when we shot 9x25 Dillon there was enough powder volume that you could make loads that would have the dot recoil down or just sit there.  Turned out having 3 more rounds in a big-stick mag that you'd only use occasionally was far more valuable.

 

 I could never shoot my 9x25 that fast... For me it turns out I needed a little bit of dot movement to help me call the shots (maybe just me)

[Chapo]

Check this out.  Finally decided on 10grs of AA7 over a 115g Everglades RN CMJ.  Used a 10lb recoil spring and loaded to 1.165" COAL.  This load felt, to me, the best on my hand and provided the least amount of felt recoil and the flattest.  This load is around 169PF.

 

 

[ltdmstr]

19 hours ago, Chapo said:

Check this out.  Finally decided on 10grs of AA7 over a 115g Everglades RN CMJ.  Used a 10lb recoil spring and loaded to 1.165" COAL.  This load felt, to me, the best on my hand and provided the least amount of felt recoil and the flattest.  This load is around 169PF.

 

 

Um, it's usually a good idea to remove the mag before you check for clear and drop the hammer.

[Chapo]

Thanks.  Gotta get rid of bad habits.  Great observation.