The only powder I've been able to find that people say a double charge won't fit, in 9mm, is 7625.
This is not quite right. There ARE powders suitable for 9mm where double charges won't fit, but with 7625, specifically, a charge for a heavy bullet could in fact be doubled and not overflow. I actually tested the limit and posted it earlier in this thread. With my Starline brass, 7625 overflowed at 8.6 grains. Anything under 4.2 grains could be double-charged without overflow. It's possible, maybe even likely, you've read people saying 7625 is safe from double charges, but what they mean is that it's bulky enough that a double-charge is so high in the case that it's hard to miss. So it's not so much "with 7625 you can't double-charge" as it is "with 7625 you're not going to double-charge" or "with 7625 it's easy to catch a double-charge."
I plan to use Berry's 147g plated. I've been using the ammo from Automatic Accuracy that uses this bullet.
If you like the Berry's 147 because of this experience and thus want to create your own bullet with a Berry's 147, you have a good chance of liking the Berry's 147.
If you want to use Berry's 147 because you want to recreate Automatic Accuracy's cartridge, you're going to have a frustrating time.
I know I can load longer. The Berry's 147 ammo I am shooting today is mixed head stamp with an OAL of 1.14. I will push test my gun when my press gets here, but here's my current plan:
To start, I will use Starline new brass (I will shift to mixed once I have a load that works well and there's no evidence of problems. I will start with the "good", move to the "bad" and not use the "ugly"), CCI 500 SPP, OAL of 1.14 or a little longer if push test allows, Berry's 147g plated bullets. I am going to start at 3 grains of SR 7625 and work up to no more than 3.5 using a chrono at each level before moving to the next level. I am looking for about a 130 power factor.
With a 124 RN grain bullet, there is some argument that seating deeper than necessary is of benefit because the bullet will seat straighter. I think a lot of people here do this with 124 RN's, me included. With a 147 grain bullet, seating deeper than necessary is of no help in that regard because the extra length of the bullet means you're already seating more than deeply enough. If Matt Mink determined that 1.14 was the best OAL because that's what his tuning with charge weight and OAL came to in terms of best accuracy and recoil properties, then 1.14 is only going to do you any good if you're using the same powder. Since that's not the case, I would recommend starting with a longer OAL, where pressures, which you are concerned about, don't shift as sharply with charge weight. With 124 grain Berry's HBRN, dropping from 1.16 to 1.14 will change your seating depth from .206 to .226, but with 147 grain Berry's RN, dropping from 1.16 to 1.14 will change your seating depth from .263 to .283. The deeper a bullet is seated, the more dramatic pressure changes are with changes to OAL. .283 is DEEP for 9mm. .206 to .226 is not that dramatic, .263 to .283 is. If you want to relieve some of your anxiety of developing a load for a bullet for which there is no published data, choose the longer OAL. That's my two, maybe three cents.
I test 10 shot strings. Some people do 5-shot strings. One off round in a 5-shot string can skew averages significantly. Go with 10, minimum. If I were going to test 3.0 to 3.5, I would load 10 rounds at 3.0, 10 at 3.2, 10 at 3.4, and 10 at 3.5. Check the average for each string as you advance. Also, after you load a magazine, turn it over backside/primer-side down, and hit it firmly against the table top, or whatever you're shooting from. Not super hard, but firmly. Some people will tell you this does no good. Others do it all the time. Before I started doing it, the first shot of most strings was slow compared to the rest of the string. After I started doing this, that anomaly vanished. It supposedly knocks loose powder stuck to case walls, breaks up any clumps, and gets all the powder in the cases in the same basic starting distribution. If you don't this, the first shot you fire will do it for all the other bullets, leaving only the first bullet you fire without this benefit. I have seen a measurable difference doing this. Give it a shot. It can't hurt.
If you decide to stick with OAL 1.14, you might get to a 130 PF at 3.4 or 3.5 grains, or it might take 3.6/3.7. I don't know. My 147gr BBI moly-coated lead get to PF 130 with 3.6 grains of 7625 at a seating depth of .295. So that's seated deeper, but it's moly vs plated. It's not apples to apples.
I am concerned that most of you are using loads way above the Hodgdon web site. Based on the load data from Hodgdon, the plan is to stop at 3.5g and make sure there's no problem. Can I go higher with this set up as long as the chrono progression is consistent and there aren't any problems on the ejected brass? Am I missing something?
You're missing experience and your own load data. If you give me a 9mm bullet right now that there is ZERO published data for with IMR 7625, even with a bullet weight I haven't worked with, I have enough of my own data with 9mm and 7625 to figure out a safe starting load. Weight comparison is obviously important, as is surface type/coating (lead, moly, plated, jacketed). But the main thing after these considerations is seating depth. The powder doesn't care about OAL. The powder cares about seating depth. And that's one of the most significant reasons why finding data for another bullet of the same weight isn't the perfect solution. Seating depth determines how much space is left in the cartridge for the powder to start its ignition and expansion. That matters a lot. As an example, I just started testing with American Select. I suspect seating depth to be the culprit for the discrepancies between my results and some published data. The first two lines below are published data. The next two lines with the Montana gold are my results.
Sierra 125gr JHP -- OAL 1.075 -- 4.6gr AmSel -- 1050 feet/sec
Speer 124gr JHP -- OAL 1.120 -- 5.0gr AmSel -- 1053 feet/sec
MGold 124gr JHP -- OAL 1.080 -- 3.8gr AmSel -- 1042 feet/sec
MGold 124gr JHP -- OAL 1.080 -- 4.0gr AmSel -- 1071 feet/sec
So there you go. This is how things can play out trying to compare different bullets to each other. My OAL is bleep close to the Sierra OAL, yet I got to almost the same velocity with 0.8 grains less powder. Why? Because despite the same weight, same bullet type -- JHP, and almost the same OAL, my bullet is seated deeper. Different bullet diameter? Probably a hair. Same thing to a lesser degree with the Speer bullet, but the longer OAL is an additional factor there. And as far apart as these numbers are with all three bullets 124/125 grain jacketed hollowpoints, how different would it be if I tried to compare the Sierra 125gr FMJ to a 124gr Berry's RN? WAY different. The point is that you can't just find load data for a bullet of the same weight with the powder you want to use and treat it like it's apples to apples. It's not.
And how about an illuminating actual apples to apples example with the Sierra 125gr FMJ and IMR 7625:
From the Hodgdon website, with IMR 7625:
Sierra 125gr FMJ -- OAL 1.090
Starting Load
4.1gr for
996 feet/sec --
Max Load
4.6gr for
1074 feet/secFrom current Sierra Reloading Manual, with IMR 7625:
Sierra 125gr FMJ -- OAL 1.090
Starting Load
4.5gr for
900 feet/sec --
Max Load
5.4gr for
1100 feet/secSame bullet. Same powder. Same OAL. Both data sets PUBLISHED. Yet the data is wildly different. Hodgdon's MAX is 0.1gr higher than Sierra's starting load. I have identified anomalies in Lapua/Vihtavuori's published data that seems to treat their manufactured bullets more favorably than other manufacturers'. Is that a product of marketing through data manipulation? Or do they just have more extensive data with their bullets? Maybe a little of both. I don't know. But what I do know: your own data is your best data. While it's great you want to settle in on a go-to bullet/powder right away, variety has its benefits, and your own data with a wide variety of bullets and powders is worth more than any single reloading manual.
You asked about some of us (me, perhaps?
) using loads outside of published data. I would suggest that this is rarer than you think it is for a not so great reason -- there often is no legitimate published data. I think I demonstrated above why this is true. Finding a bullet close in weight or type is sometimes the best option we have, but it's hardly the same as having published data for a particular bullet and powder at the OAL you need. And if there is no published data, we can't be operating outside of it. It's a guideline. And you'd be well-advised to respect that guideline with starting loads, but beyond that... max loads... your chrono, your experience, and the experiences of others might be just as valuable. What I'm doing, and some others, is monitoring velocity increases relative to powder weight increases and judging by that whether or not pressures are okay. Others rely on reading primers. I look at primers, but I trust chrono data to a greater degree. Those relying solely on reading primers with pistol rounds are probably getting to higher pressures than those reading velocity trends.
Also, if max standard pressure for 9mm is 34,000 (35,000?) and Hodgdon's data for a max load is 31,000 then their max isn't the actual max. Will you get there with the next 0.1gr? Maybe. If you go above that, does the gun blow up? Doubtful. And definitely not if it's rated to take +P ammo, which goes up to 38,500 PSI. And even then, healthy cases in guns built for it can handle a few thousand pounds more than that. So am I worried that going 0.1 or 0.2 grains above max published data? I'm not. Are their drawbacks? Yes -- wear and tear on the gun and on your brass, plus the risk of brass ruptures if you're not using healthy brass. Yet another consideration is just how good is your measuring equipment? That's something else to consider before pushing a little bit beyond published loads.
Basically, if you have the experience, know-how, and confidence in your gear, and you are aware of the risks and how to evaluate them, venturing
a little above max published loads can be done safely.
Edited about 15 times for clarity and type-o's. Might need a few more.
