Notes on working up loads for 40 S&W

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Vonz90
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Notes on working up loads for 40 S&W

Post by Vonz90 » Tue Jan 12, 2021 5:12 pm

Dies came in on Saturday so I started loading for with the 155gr XTP bullets.

A few observations- started using the CCI 5.56 NATO primers that I bought a few years ago. They do not work for crap in my AR nor in this application. I need to give them away or pitch them.

The CCI small rifle primers seem to work fine.

Hodgdon data for Longshot with the 155 XTPs runs 7.5-9.3 grains, 1,129-1283 FPS for 4 In barrel but only 31,900 PSI. 40 S&W is rated to 35,000 PSI so pretty conservative. Looking around; some people on different reloading forums report loading it up to 11+ grains and 1400 FPS. I have no desire to go that high, but good to know there is margin.

I talked about muzzle energy before but momentum is actually what is conserved in the system (ME is easier to look up though). I calculated that the loads which work reliably for my P99c have a momentum around 27 lbs-ft/s (book value from 4 inch barrel), so I am setting that as my minimum goal.

That works out to needing 1220 FPS with a 155 gr pill. I will probably go over a bit to be sure and a little extra energy will not hurt if I end up in a pinch using these as defensive rounds. Also, since I have a 3.5 and 3.2 in barrel pistols and Longshot is a slower powder some, I probably need a bit more to get to the same place as I am seeing with the faster powders in the Gold Dot and Sig loads.

I did three steps from minimum to get to 7.8 grains. I saw one FTE out of 15 at that load. Not a surprise as I only have about 25.6 lbs-ft/s at that load and per the benchmark above I need to get about 10% higher than that. Still, that is already better than the Federal aluminum case stuff.

I will pick it up later this week. I think I will have to go to about 8.5-8.8 gr to get what I want but probably do it in two or three steps to be on the safe side.
Last edited by Vonz90 on Wed Jan 13, 2021 9:53 pm, edited 2 times in total.

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Captain Wheelgun
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Re: Notes on working up loads for 40 S&W

Post by Captain Wheelgun » Tue Jan 12, 2021 9:07 pm

How did the CCI 5.56 primers fail? I have a bunch that I originally bought for loading 5.56 but also want to use on high end .327 Federal loads.
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Vonz90
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Re: Notes on working up loads for 40 S&W

Post by Vonz90 » Tue Jan 12, 2021 9:12 pm

Captain Wheelgun wrote:
Tue Jan 12, 2021 9:07 pm
How did the CCI 5.56 primers fail? I have a bunch that I originally bought for loading 5.56 but also want to use on high end .327 Federal loads.
No go bang.

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Gunnuts
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Re: Notes on working up loads for 40 S&W

Post by Gunnuts » Wed Jan 13, 2021 3:05 pm

5.56 primers harder than regular? That would be my guess for no bang in a handgun load.

Never throw away primers that haven't been deactivated...especially these days. :shock:

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Vonz90
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Re: Notes on working up loads for 40 S&W

Post by Vonz90 » Wed Jan 13, 2021 8:25 pm

Gunnuts wrote:
Wed Jan 13, 2021 3:05 pm
5.56 primers harder than regular? That would be my guess for no bang in a handgun load.

Never throw away primers that haven't been deactivated...especially these days. :shock:
That is what I figure as well, but my AR does not like them either, I see about 1 dude per magazine with them. Suppose I could try a stronger hammer spring, but it runs well with everything else so I am not worried about it.

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Netpackrat
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Re: Notes on working up loads for 40 S&W

Post by Netpackrat » Wed Jan 13, 2021 8:41 pm

They also make an enhanced firing pin with more protrusion intended for running steel case Golden Tiger in AR-15s, which may make a difference here. It is not recommended for use with standard ammo/primers though.
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Vonz90
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Re: Notes on working up loads for 40 S&W

Post by Vonz90 » Mon Jan 18, 2021 7:01 pm

I walked the loads all the way up to 9.0 grains of Longshot (max book is 9.3). Even at 9.0 that is quite a hot load and really more than I think I need.

I have not seen any FTE above 7.8 grains of Longshot, On that batch my OAL was a tad long so I think even that would probably be fine at the OAL 1.125 (1.125 is correct, that batch was sitting more like 1.135, it was only the second batch I did and I was still dialing that variable a bit). So I think the pressure there was likely on the low side of what that load should be.

I did a little bit of a larger batch of 20 at 8.4 grains. They functioned fine and shot accurately enough but seemed a bit hotter than I think I need and compared to the factory ammo that works well.

So, I rechecked my calculations on the loads that have been working well for me and I had misrememberd the correct momentum number. (As noted above I thought it was like 27ish lb-ft/sec but it was actually more like 25- 26, so I have more margin than I was thinking I did (the ones that I have had issue with are more like 23-24). I dropped the numbers for the good ones in the same spreadsheet for comparison along with Hornady's XTP numbers just as a benchmark.

I am thinking I will go with 8.0 grains - linear interpolation from the book value tells me that should be 1171 ft/sec which is very close to the load Hornady advertises for their 155 grain XTP defensive ammo and would put it right in the middle of the momentum values that have worked well for me. I will do up a bit of a larger batch to try next weekend. If it shoots clean I will probably go with that load for the XTPs. The purpose of this load would be practice / backup defensive load (at least until I can find 165 or 180 grain hollow points in stock somewhere).

The coated bullets have not arrived yet, when they do that will come next but that will only be practice load.
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Precision
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Re: Notes on working up loads for 40 S&W

Post by Precision » Wed Jan 20, 2021 3:50 pm

When choices are available, you may want to reference this link from Lucky gunner before buying more pills.

https://www.luckygunner.com/labs/self-d ... ests/#40SW
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Vonz90
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Re: Notes on working up loads for 40 S&W

Post by Vonz90 » Sat Jan 30, 2021 6:23 pm

Did a batch at 8.0 grains and it did fine so that is what I will load up for the 155 XTPs. I guess I could have just loaded the book value to get the claimed Hornaday factory ammo velocity and it would have put in the same place but now I know that is right for what I have. Also, it allowed me to validate that all else being equal the FTE issue goes away with above a certain energy threshold, and that is good to know.

I will start on the coated bullets when I get them; still no sign of them arriving.

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