OAL vs Minimum Insertion Depth??

[ElDub1950]

Just rechecking to get your opinion: Is 1/10 inch insertion depth enough?

I just got my first 9mm 124gr RN Xtreme bullets and will be working up some loads with my Titegroup and Autocomp.

Hodgdon's site shows the OAL at 1.15 and my reloading book says 1.13, but everyone seems to quote these specs with Berry's Bullets. I don't know how the profile varies between Xtreme and Berrys.

But with a case length of .747" and bullet length of .505", an OAL spec of 1.15" leaves only one tenth of an inch inserted in the case. That just doesn't seem like enough to seat firmly. But I'm new, so wanted to ask.

Now, I'll probably go about 1.13 and since I'm starting near the Min Load it should be fine.

[twotacocombo]

As long as the bullet isn't falling out or jamming into the rifling, it's not too long. Two one-hundredths of an inch isn't going to make much of a difference if the bullet isn't secure in the brass at 1.15". As long as the case is sized properly, there should be enough tension to hold the bullet in place even at the depth you can press it in by hand.

[ElDub1950]

Yeah, the 2/100s isn't significant, and of course cycling and chambering is the key. Mostly just wondering if there's some generally accepted standard. Someone on some forum stated the min is half the bullet diameter, but no idea if he actually knows anything.

[CGT80]

1.150" seems long and 2 tenths doesn't seem like much in the case, but but it is hard to visualize.

I had to read your post twice because I am used to working with three decimal places for ammo length. For example 1.150" vs. 1.15". 0.747" is easy to read. I don't know if it is standard practice to add the 0 to the end or not. It seems I always see three digits in books. But I am picky that way, since it is easy to confuse 1.015" with 1.15", for me. Your math is right and dropping off the 0 is common in many cases. My weird mind thinks as thousandths as a whole number, when referring to guns, and a ten thousandths as a fraction. Such as 0.4523" is 0.452 3/10ths. Never mind my ways of dealing with math, I just thought it was interesting how people look at it in different ways.

I have used various 9mm bullets and I don't think I have ever gone past 1.135" COAL. You could load up some at both lengths, with the minimum charge, and shoot the longer one first. If all is good, then try the shorter one. You might want to rack the slide, assuming a semi auto pistol, with a loaded round chambered, and see if it extracts the entire round. Of course the plunk test will tell you this as well, with your dummy ammo. You can hold the round of ammo in your hand and push the nose of the bullet against a hard metal surface to see if the bullet stays put or if the case tension is bad. You could try pulling the bullet with your fingers as well. Run some dummy rounds through your gun by hand and see if they both feed well.

I have never heard of a rule like half the bullet diameter has to be in the case, but it doesn't mean it hasn't been used before. The max listed load is usually safe for a newer well built pistol, and it should be a bit less than what the actually max for that cartridge spec is. If you are using a starting load, then you should have a lot of room for pressure increase that may result from a bullet that is seated deeper. I doubt you will even feel a difference in recoil between the two, at a minimum charge.

It sounds like you are on the right path.

[ElDub1950]

1.150" seems long and 2 tenths doesn't seem like much in the case, but but it is hard to visualize.

I had to read your post twice because I am used to working with three decimal places for ammo length. For example 1.150" vs. 1.15". 0.747" is easy to read. I don't know if it is standard practice to add the 0 to the end or not. It seems I always see three digits in books. But I am picky that way, since it is easy to confuse 1.015" with 1.15", for me. Your math is right and dropping off the 0 is common in many cases. My weird mind thinks as thousandths as a whole number, when referring to guns, and a ten thousandths as a fraction. Such as 0.4523" is 0.452 3/10ths. Never mind my ways of dealing with math, I just thought it was interesting how people look at it in different ways.

I have used various 9mm bullets and I don't think I have ever gone past 1.135" COAL. You could load up some at both lengths, with the minimum charge, and shoot the longer one first. If all is good, then try the shorter one. You might want to rack the slide, assuming a semi auto pistol, with a loaded round chambered, and see if it extracts the entire round. Of course the plunk test will tell you this as well, with your dummy ammo. You can hold the round of ammo in your hand and push the nose of the bullet against a hard metal surface to see if the bullet stays put or if the case tension is bad. You could try pulling the bullet with your fingers as well. Run some dummy rounds through your gun by hand and see if they both feed well.

I have never heard of a rule like half the bullet diameter has to be in the case, but it doesn't mean it hasn't been used before. The max listed load is usually safe for a newer well built pistol, and it should be a bit less than what the actually max for that cartridge spec is. If you are using a starting load, then you should have a lot of room for pressure increase that may result from a bullet that is seated deeper. I doubt you will even feel a difference in recoil between the two, at a minimum charge.

It sounds like you are on the right path.

LOL, yeah, numbers ... I spend all my time looking at numbers in reports, databases and spreadsheets. Always having the same number of decimal places makes it easier to read in those formats.

I always start with a handful of dummy rounds, do plunk checks and cycle them through my guns a few times first. With my reloading so far, accuracy came in about mid range on the load chart and I'm expecting I won't have any reason to go near the max loads with these new bullets either.

Thanks for your input.

[J-cat]

Hodgdon's data is based on the 124 HBRN which has a longer shank and greater bearing surface. So you can seat them out more while maintaining adequate case tension.

I like 1.125" with the Xtremes or other non hollow base 124gr bullets.

[Leethe4th]

Yeah, the 2/100s isn't significant, and of course cycling and chambering is the key. Mostly just wondering if there's some generally accepted standard. Someone on some forum stated the min is half the bullet diameter, but no idea if he actually knows anything.

Yes, actually 2/100 is significant, depending on what bullet weight and style. 2/100 = .020" which may be enough to keep it from gageing correctly. The convention is 10 ths (.10"), 100 ths (.010"), 1000 ths (.001") and 1/1000 ths
(.0001"). You will only measure to 3 significant digits on a caliper anyway for OAL. A few thousands won't matter, as most presses will vary
.000-.005" on seating depth anyway. Never heard of the half bullet diameter rule.

These 3 bullets are the same powder charge, 4 grains of TiteGroup at 3 different OALs.

Bear Creek 125 grain Round Nose, OAL = 1.065 - 1.070"
Bear Creek 125 grain Truncated Cone OAL = 1.095 - 1.100"
Montana Gold 125 grain JHP OAL = 1.165 - 1.170"

If the Round Nose bullets are seated to 1.085" they will not case gage.





10 ths on the rack (main scale) and 1000 ths on the dial, reading .384".

[ElDub1950]

These 3 bullets are the same powder charge, 4 grains of TiteGroup at 3 different OALs.

Bear Creek 125 grain Round Nose, OAL = 1.065 - 1.070"
Bear Creek 125 grain Truncated Cone OAL = 1.095 - 1.100"
Montana Gold 125 grain JHP OAL = 1.165 - 1.170"

Yes, that's exactly why I was asking about the difference between Berry's and Xtreme bullet profiles. Most books include Berry's not Xtreme and I don't have any Berry's to compare.

[Leethe4th]

Yes, that's exactly why I was asking about the difference between Berry's and Xtreme bullet profiles. Most books include Berry's not Xtreme and I don't have any Berry's to compare.

Start at 1.170" and keep backing off until they case gage.

[CGT80]

Great visuals, Lee!

For COAL, I use digital calipers and for bullet diameter I use digital micrometers. Most measurements for reloading are only to three decimal places and I agree that a few thousandths isn't real important in COAL. That is why I find the max length that my gun will handle and then go 10 thousandths deeper. The lengths will vary on my presses. For casting and sizing bullets I will use the fourth decimal place, but it is just for reference. A little big on a cast boolit is just fine.

Looks like I said two tenths above and it should have been one tenth. Maybe I shouldn't post numbers when I am tired.

[Leethe4th]

Great visuals, Lee!

. That is why I find the max length that my gun will handle and then go 10 thousandths deeper. The lengths will vary on my presses. For casting and sizing bullets I will use the fourth decimal place, but it is just for reference. A little big on a cast boolit is just fine.

:

That's my method also, load them as long as they can go, keeping in mind that exceeding a maximum OAL can cause magazine problems, while starting at the lowest charge weight per the powder makers website load data. Then check for accuracy and chrono for power floor for competition.