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How to adjust for OAL


CrashDodson

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I am new to reloading. I actually have yet to reload a round. After several hours I now have my new dillon 550 on my bench. I assembled it using the DVD from dillon. Just waiting on bullets to finish the setup. I have a few different loading manuals and have been reading online for months.

I recently purchased a STI 2011 limited gun and the previous owner recommended:

4.7 Grains Ram Shot Comp

180 Bayou Bullets

1.2 OAL

.420-422 Crimp

I spoke with someone else that is running 4.6g ramshot comp on 180g with a 1.180 OAL.

These are major PF loads.

My confusion comes when looking at the load data from ramshot. I want to work up a major and minor load using ramshot and 180g ibejihead coated bullets. Depending on bullet type the ramshot load data has starting loads as low as 2.9 grains with max loads at 4.0 grains for 180g bullets. Why is it ok to load past the max load data from ramshot? I know OAL impacts pressure. The ramshot OAL is 1.115. How do you safely adjust for a longer OAL?

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This is something that I don't think enough people pay attention to, and it's very important. That being said, there are a lot of people doing it, and there don't seem to be a lot of problems.

When you load long the first inclination is that you've lowered the pressure from what it would have been with a spec OAL, but then you have to use more powder to get up to the velocity that will make major, which is going to bring the pressure back up.

So what exactly are you loading? A long .40...

...or a short 10mm?

I don't have any load data for ramshot in 10mm, so I don't know what a 4.7g load would be pressure wise wrt. 1.25" OAL. Powder doesn't necessarily burn at a linear rate when you get outside it's optimum range, and I don't like the idea of just bumping a charge beyond tested loads without some clue as to how the pressure behaves... but maybe that's just me, YMMV.

Personally, I would be looking for a powder that has data for both the .40 and the 10mm. More specifically one that has a pretty good spread from starting load to max, and I would be suspicious of one that takes more powder in long .40 to make velocity than a 10mm starting load. The 10mm case is rated for more pressure than the .40.

HTH,

Dave

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If you're new to reloading, I'd seriously suggest you work up Very Slowly

to Major with a .40 (from your description above, it sounds like you're

loading .40).

Loading .40 to major is dangerous ... :ph34r:

Your OAL is very important ...

Your "crimp" is very important ....

Your powder charge is obviously very important ... but most beginners

forget how important OAL and "crimp" are - they can cause damage.

I'd establish your OAL first using The Plunk Test.

Then I'd work on the "crimp" - you want to remove the bell produced to

permit you to seat the bullets. Too little "crimp" and the cartridges will

NOT fully seat in the chamber. Too much "crimp" and your accuracy

will suffer.

Then, I'd load up some Minor loads - PF 140 - 150, and test them

to ensure the bullets do not "set back" when seriously pushed -

bullet set back can blow up your gun with fast powders and heavy

bullets.

I would NEVER try to load .40 major without a chrono.

After successfully loading and firing a few hundred rounds of

Minor, I'd work up slowly, with the chrono, to major, checking

constantly for the problems mentioned above.

Good luck with your new venture and new gun. :cheers:

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thanks for the replies. I have a chrono but I dont have anyway to measure pressure. Ramshot does have a 10mm load i found.

SIERRA JHP 7.5 1,110 8.4 1,210 34,400 1.260

I would be loading a long 40. 40s&w with 1.2 OAL

Edited by CrashDodson
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+1 on using the chrono. Foolish to try to figure out a hot load without knowing what the bullet is doing. Follow the advice given and watch for primer flattening as one sign you are getting too hot with that powder. And be sure if you use any previously fired cases that you check them carefully for the Glock bulge or any cracking. I visually check all - yes, all - of my 40S&W cases after they are loaded to see if any cracked or were otherwise compromised during the reloading process. If so, they are disassembled and trashed. This is even more important if you are trying for major power.

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I would be loading a long 40. 40s&w with 1.2 OAL

The reasoning behind the comment is that when you make a .40 S&W longer, you have a 10mm with a shorter case. SAAMI max OAL on .40 S&W is 1.135", while max OAL on 10mm auto is 1.26. So, at 1.18" to 1.20" you're somewhere in between. That's where the discrepancies that you see between long .40 recommended by experienced reloaders and book data held to SAAMI lengths comes in.

All other things held equal, seating the bullet into the case deeper pushes up your pressure. Not seating it in as deep reduces your pressure, which lets you add more powder until you're at max again. Make sense?

Where this comes into play is with faster burning powders and people attempting to make major with them. It's entirely possible to have a load that starts to exhibit pressure signs at 1.135" OAL that does not make major, but by seating the bullet out several hundredths beyond that, you're able to work up to one that does make major while still being safe.

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+1 on using the chrono. Foolish to try to figure out a hot load without knowing what the bullet is doing. Follow the advice given and watch for primer flattening as one sign you are getting too hot with that powder. And be sure if you use any previously fired cases that you check them carefully for the Glock bulge or any cracking. I visually check all - yes, all - of my 40S&W cases after they are loaded to see if any cracked or were otherwise compromised during the reloading process. If so, they are disassembled and trashed. This is even more important if you are trying for major power.

I did see some cases with glock buldge. I resized a few while playing with the new 550 and the cases drop in fine in the the case cage and in my barrel. Do I still need a bulge buster or equivalent?

+1 on using the chrono. Foolish to try to figure out a hot load without knowing what the bullet is doing. Follow the advice given and watch for primer flattening as one sign you are getting too hot with that powder. And be sure if you use any previously fired cases that you check them carefully for the Glock bulge or any cracking. I visually check all - yes, all - of my 40S&W cases after they are loaded to see if any cracked or were otherwise compromised during the reloading process. If so, they are disassembled and trashed. This is even more important if you are trying for major power.

Sent from my SM-N910V using Tapatalk

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I would be loading a long 40. 40s&w with 1.2 OAL

The reasoning behind the comment is that when you make a .40 S&W longer, you have a 10mm with a shorter case. SAAMI max OAL on .40 S&W is 1.135", while max OAL on 10mm auto is 1.26. So, at 1.18" to 1.20" you're somewhere in between. That's where the discrepancies that you see between long .40 recommended by experienced reloaders and book data held to SAAMI lengths comes in.

All other things held equal, seating the bullet into the case deeper pushes up your pressure. Not seating it in as deep reduces your pressure, which lets you add more powder until you're at max again. Make sense?

Where this comes into play is with faster burning powders and people attempting to make major with them. It's entirely possible to have a load that starts to exhibit pressure signs at 1.135" OAL that does not make major, but by seating the bullet out several hundredths beyond that, you're able to work up to one that does make major while still being safe.

To ensure I am being safe as I worked a load up trying to get the fps for major, I need to not exceed the max fps from the load data and check the cases for signs of pressure damage?

Sent from my SM-N910V using Tapatalk

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I would be loading a long 40. 40s&w with 1.2 OAL

The reasoning behind the comment is that when you make a .40 S&W longer, you have a 10mm with a shorter case. SAAMI max OAL on .40 S&W is 1.135", while max OAL on 10mm auto is 1.26. So, at 1.18" to 1.20" you're somewhere in between. That's where the discrepancies that you see between long .40 recommended by experienced reloaders and book data held to SAAMI lengths comes in.

All other things held equal, seating the bullet into the case deeper pushes up your pressure. Not seating it in as deep reduces your pressure, which lets you add more powder until you're at max again. Make sense?

Where this comes into play is with faster burning powders and people attempting to make major with them. It's entirely possible to have a load that starts to exhibit pressure signs at 1.135" OAL that does not make major, but by seating the bullet out several hundredths beyond that, you're able to work up to one that does make major while still being safe.

To ensure I am being safe as I worked a load up trying to get the fps for major, I need to not exceed the max fps from the load data and check the cases for signs of pressure damage?

Sent from my SM-N910V using Tapatalk

The velocities your load data gives you and the velocities you accomplish by changing some of those variables aren't going to give you a hard and fast comparison point. By definition you're trying to push the bullet faster than certain load data. The pressure signs become much more important, and unless you have a piezo kit this is where considerable experience as well as a little bit of lore come into play (things like Clays and N310 eating up case heads, for example).

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...

Your OAL is very important ...

Your "crimp" is very important ....

Your powder charge is obviously very important ... but most beginners

forget how important OAL and "crimp" are - they can cause damage.

...

The Competition Reloading DVD featuring Brian has really good close-up illustrations on OAL and crimp, especially crimp. Brian intentionally over-crimps a round, so you can see what that looks like and learn why it is a problem. He also helps you understand what a proper crimp looks like and what the crimp measurement should be: bullet diameter + double the case wall thickness.

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Crash, your best bet is to get one of the local hosers who shoots major help you out. You can read and watch all you want, but there is no substitute for experience and a hands on setup.

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From my point of view as a new reloader, yes, the DVD is really valuable. The format is such that it's like being in a reloading room with Brian, and the interviewer (Lenny Magill I believe) asks questions a beginning reloader might ask with Brian answering the questions and showing/demonstrating on a 650. There is some good voice-of-experience advice on safety in the video.

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