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What to watch for in pressure and chrono while working up loads?


Nicholas.Ellis

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I just started reloading, and am working up a load to shoot major.

Components:

230 grn winchester FMJ

CCI primers

Win brass

OAL 1.250

straight Clays

Shooting out of a 5' stock Kimber

I've got ten rounds each loaded for 3.8, 3.9. 4.0, 4.1, 4.2, and 4.3 grains of straight Clays, dropped from a Dillon 550.

My question:

As I chrono these loads, what should I be watching for? My goal is to reach major, not to push the boundaries of the load. What are the danger signs as I work up higher in pressure?

Edited to ask: By the way, any suggestions besides the FMJ, pros/cons? I had a bunch of them and used them, didn't think much about other bullets.

Edited by Nicholas.Ellis
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Chrono those until you make Major with enough margin to spare to be happy. As for pressure signs, if you see any you've gone too far. The .45 ACP runs in the 17,000 to 20,000 range. handgun don't show much if any signs of pressure until they get up to 40,000.

As for bullets, there's a reason we all used the H&G 68 or its equivalent back in the old days. Easy to load, accurate and reliable in feeding.

I just started reloading, and am working up a load to shoot major.

Components:

230 grn winchester FMJ

CCI primers

Win brass

OAL 1.250

straight Clays

Shooting out of a 5' stock Kimber

I've got ten rounds each loaded for 3.8, 3.9. 4.0, 4.1, 4.2, and 4.3 grains of straight Clays, dropped from a Dillon 550.

My question:

As I chrono these loads, what should I be watching for? My goal is to reach major, not to push the boundaries of the load. What are the danger signs as I work up higher in pressure?

Edited to ask: By the way, any suggestions besides the FMJ, pros/cons? I had a bunch of them and used them, didn't think much about other bullets.

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i think the 4.3 is pushing it a bit, but if you're barrel's loose, who knows. usually about 4.0 will get you major(716 fps). clays is pretty fast, and fast powders build pressure real quick!! .1 of a grain in clays w/230's definitely means something! experimenting w/ your chrono is the only way to tell. and anything over major is just experimenting with accuracy. clay's is definitely the shizzit w/230's in .45's though. i think most people here will agree......

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I loaded up some rounds with 3.8 and 4.0 clays and 230gr Frontier (plated) bullets. On a cold day (max of 40) the max I could get out of a new G21 was 154 pf. I didn't have my 1911 with me to try, but some folks seem to get major with 4.0 and some don't. I'll be interested to see what your crono numbers are.

Bruce

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Thanks, I'll keep working up and chrono'ing until I get to major. Seems pretty straightforward.

I didn't figure that I would see any physical signs of pressure, but rather was wondering in terms of the velocity. Is there any standard variations that typically happen to the velocity that I should watch for as I work my way up through the pressure? Does the velocity plateau at some point, where a further increase of pressure doesn't do much for the velocity?

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Some guns will take as much as 4.5 grains. The original data from Clays listed 4.7 as max with a 230 FMJ, Hodgdon didn't change the powder, just the load data according to them.

Clays will flatten out when it approaches the point where it goes nasty. For instance (and just as an example) if you are getting 10 fps per tenth of a grain as you work up all is good. Then it drops to 3-5 fps per tenth, add another tenth and it doesn't make the full 10 either, now you need to pay close attention. You are approaching the point where Clays goes squirrelly and you cannot predict what will happen next. It might actually slow down with more powder, and it might spike pressure badly.

As long as the speed increase per charge weight increment is linear you will be fine.

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4.0 gr of Clays, Winchester LP primers, 230 gr Zero FMJ or JHP give me a PF of 170 to 173 out of my 5" 1911 depending on the brass. I suggest once you hit the PF you want that you hold off on rounds with more than one incrment of powder greater.

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Anyone care to speculate what the pf difference would be with same load shot out a new G21 (4.6") and a 5" 1911 Springer Mil-Spec with under 1500 rounds through it? I'm trying to see if I can use the same .45 acp load in SS and L-10 in the 2 different guns? Like I said above, 4.0 Clays got me 154pf out of my G21 on a cold day.

Bruce

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Bruce, the G21 will make a max of 160 on a HOT day and maybe not that much. Strange, Glock barrels are usually on the fast side. Smells a bit of an aftermarket barrel to me....

Each barrel is an individual. The only way to tell what they will do is to shoot them over a chrono with the ammo and see what happens.

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You should be just fine with that load. With 230FMJ my OAL is shorter, around 1.230, and I load 4.3gr of CLAYS for around a 173PF in my REVOs. The same load is around 175PF in my autos, but the load is so damn soft I dont even notice it, and there is no pressure issues.

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You should be just fine with that load. With 230FMJ my OAL is shorter, around 1.230, and I load 4.3gr of CLAYS for around a 173PF in my REVOs. The same load is around 175PF in my autos, but the load is so damn soft I dont even notice it, and there is no pressure issues.

Ditto the above- My SW625, my SW745 IPSC, and my brother's SW1911 all turn in ~174-177 with the EXACT SAME dimensions and load... :cheers:

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Standard 5" 1911 load for years was a 200 Gr. HG68 OAL 1.250" with 4.2 Clays for 860 f/s 172PF.

Now 4.2 Clays with about any 230 plated/jacketed bullet OAL 1.230-1.250" gives 760 f/s 174PF out of a 5" 625 and when run thru my "old" 5" Clark Match Barreled 1911 it gives 790 f/s 182PF.

3.9 Clays with 230 plated/jacketed bulets out of the above 1911 give 750 f/s 172PF.

Have loaded 230 JHP with more than 4.3 Clays and never saw any pressure, but felt the power!

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