Advice on 9mm OAL [Archive] - Glock Talk

PDA

View Full Version : Advice on 9mm OAL


modelflyer2003
04-05-2010, 21:57
I reloaded my first batch of 9mm, and I want your advice. I made 18 rounds of 115 gr. round nose, Berry plated, Hodgdon Universal 4.2gr, OAL 1.156. I arrived at the OAL after measuring one of my factory UMC rounds. I am not sure what OAL to set. They fit fine in my gage. Range report. I had one failure to chamber. When I dropped the magazine and ejected the round, I saw that the plating got scratched up in the process of chambering. I wondered if it failed to feed because of the OAL or possibly because the low charge (4.2 gr of Universal) failed to move the slide adequately enough. The other rounds worked fine. I am using the deluxe press from Lee and the dispenser seems to not be 100% accurate. I made another lot with the same diameter and powder charge and I will shoot them later this week. Should I change the AOL on them? I believe making them shorter will increase the pressure and the velocity. I donít own a Chrony. My Lyman 49th Ed manual gives only the Max OAL, and the Hodgdon data from the website does not give OAL either. What do you think?<!-- google_ad_section_end -->

chemcmndr
04-05-2010, 22:49
Well, the Lyman Manual does give Min OAL, but if I remember correctly, their 115 grain sample bullet was a Hornady XTP (hollow point). The max OAL for 9mm was listed as 1.169" in Lee's Modern Reloading. Depending on the powder, the minimum OAL is somewhere around 1.125" (going off of memory, so I would need someone to verify that). I've read that you get better accuracy from using an OAL closer towards the maximum side, so I wouldn't change your OAL. When I was making my test loads using same powder and bullet, I had an OAL of 1.150" and was starting out at 4.5 grains. The rounds did very well out of my Glock 17. What weapon are you using?

modelflyer2003
04-05-2010, 23:06
Glock 26. Thanks for you help. I wondered if I was doing right with my OAL. After I shoot what I have made this evening, I think I will increase the powder a little. What is the likeliest reason for the Failure to Chamber? Thanks.

robin303
04-05-2010, 23:38
I might be wrong but I try to set my OAL the same with my 9mm round nose with all grains at 1.135. With hollow points and flat points I set at 1.120. This is with 5 different powders and so confident that I actually have two separate dies that I used lock tite to set them with. That was taking account all the books and data from the net and they work fine in my 9mm Glocks. Just reload 10 rds at 0.1 increments until you find a favorite load. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

sourdough44
04-06-2010, 05:26
I've loaded a Rainier plated 115 grn RN bullet at 1.10 COL. My powder was 4.2 grns of Titegroup. Yes your powder charge is a little on the low side, O.K., if they cycle fine. I came to my COL of 1.10 from listed data, maybe the Hodgdon manual, maybe website too. FYI, I got a 1087 fps average with the 4.2 grns of TG.

ron59
04-06-2010, 07:07
I might be wrong but I try to set my OAL the same with my 9mm round nose with all grains at 1.135. <o:p></o:p>

I am by no means an expert, but I did a BUNCH of research prior to loading my first batch, looking for both suggested powders, and looking at OALs as well.

1.130 - 1.135 appears to be a very common range.

I "neglected" that advice, and went with a much longer OAL of 1.155 and ended up with light loads that shot fine, but were inaccurate. Of course, I could have just dumped MORE powder in, but decided instead to lower my OAL down and worked my load up again. This time I was most interested in achieving a certain power factor (130'ish), and the accuracy I'm getting now is WAY better.

Colorado4Wheel
04-06-2010, 07:35
You could load that bullet at 1.100 to 1.170 and not have problems. It's your charge that is more then likely the problem. The G26 is not as tollerant of low power loads. Personally, I would shorten the length to 1.130 and get the charge into the middle range of that powders data. Assuming the reloading data supports my OAL recommendation (which I have never seen one that doesn't). Do your own research.

FiremanMike
04-06-2010, 08:25
I will say (without a chrono) that OAL when I load 9mm seems to effect felt recoil, so I would assume it would effect pressure/velocity as well. My first batch of titegroup 4.2 at 1.155 was also extremely light. Switching it to 1.130 made a significant difference. I settled at about 1.140 and stuck with that..

tlafrance
04-06-2010, 08:32
1.130-1.135 on ANY RN profile projectile.

Tom

XDRoX
04-06-2010, 10:18
If it fit in a case gauge then I doubt it caused the problem. I have loaded from 1.130 to 1.165 without issues. My guess is your charge was to light. It couldn't hurt to drop your OAL a little though. I load all my 115 RN to 1.140 FWIW and they perform great.
The 26 has a pretty stiff spring IMO, so a low charge may be the culprit.

ron59
04-06-2010, 10:53
I will say (without a chrono) that OAL when I load 9mm seems to effect felt recoil, so I would assume it would effect pressure/velocity as well. My first batch of titegroup 4.2 at 1.155 was also extremely light. Switching it to 1.130 made a significant difference. I settled at about 1.140 and stuck with that..

Well duh.... decreasing the OAL while maintaining the same amount of powder increases pressure. You're putting the SAME amount of powder into a smaller "space" (decreasing OAL pushes the bottom of the bullet further into the case).

So yes, you're increasing the pressure, and thus increasing the recoil.

When you made the significant of a jump in OAL, I would have dropped powder some and then retested with a chrono.

fredj338
04-07-2010, 12:47
Well duh.... decreasing the OAL while maintaining the same amount of powder increases pressure. You're putting the SAME amount of powder into a smaller "space" (decreasing OAL pushes the bottom of the bullet further into the case).

So yes, you're increasing the pressure, and thus increasing the recoil.

When you made the significant of a jump in OAL, I would have dropped powder some and then retested with a chrono.
Well yes & no. Pressure will certainly increase as the bullet is seated deeper, but pressure are NOT the cause for increased recoil, velocity is. Yes, usually as pressures go up, vel also go up, but not always. I can reach max pressure in a 9mm w/ uberfast powders & still be far from the recoil of the same bullet going 100fps faster w/ slower powder causng less pressures.:dunno:

Colorado4Wheel
04-07-2010, 12:53
Same velocity and fast powder will have lower percieved recoil then a slow powder.

fredj338
04-07-2010, 12:53
If it fit in a case gauge then I doubt it caused the problem. I have loaded from 1.130 to 1.165 without issues. My guess is your charge was to light. It couldn't hurt to drop your OAL a little though. I load all my 115 RN to 1.140 FWIW and they perform great.
The 26 has a pretty stiff spring IMO, so a low charge may be the culprit.

Keep in mind that case gages do NOT measure OAL as much as headspace & cartridge spec diameter. There is no rifling to engage so your bbl has to be used as final gage for proper OAL.

XDRoX
04-07-2010, 12:57
Keep in mind that case gages do NOT measure OAL as much as headspace & cartridge spec diameter. There is no rifling to engage so your bbl has to be used as final gage for proper OAL.

I did not know this. Thanks Fred.

fredj338
04-07-2010, 13:01
I did not know this. Thanks Fred.
Yep, you magazine design & chamber/rifle in YOUR bbl are what determine max OAL. A case gage is great, but not definative. Always setup usiog the bbl as a gage, then use the case gage as final spot or final check to make sure you have proper crimp & sizing.

Colorado4Wheel
04-07-2010, 13:09
If you are a case gauge'r the process works like this.

1) Determine correct max OAL using your barrel. Then load a little bit shorter to insure normal oal length variations don't cause any issues in use.
2) Load the ammo and check OAL/weight as you go and as any safe reloader would do.
3) Case gauge the ammo, use your finger to check for high primers
4) Put the ammo in plastic boxes.
5) Final visual inspection of primers and length while in box.
4) Inspect

fredj338
04-07-2010, 13:39
If you are a case gauge'r the process works like this.

1) Determine correct max OAL using your barrel. Then load a little bit shorter to insure normal oal length variations don't cause any issues in use.
2) Load the ammo and check OAL/weight as you go and as any safe reloader would do.
3) Case gauge the ammo, use your finger to check for high primers
4) Put the ammo in plastic boxes.
5) Final visual inspection of primers and length while in box.
4) Inspect

You are good Steve!:supergrin:

Patrick Graham
04-07-2010, 14:31
I'm seating my Berry's 115 RN loads to 1.14".

I haven't had a failure to feed and chamber yet.

Colorado4Wheel
04-07-2010, 14:38
You are good Steve!:supergrin:

Well, I did get two #4's the last one is just a mistake.

GioaJack
04-07-2010, 14:40
Well, I did get two #4's the last one is just a mistake.



More of that flatlander math. :whistling:

Jack

fredj338
04-07-2010, 16:00
Well, I did get two #4's the last one is just a mistake.
I said your were good, no that you could count! Must have gone to public school!:rofl:

Bamamedic
04-12-2010, 17:25
Measuring using calipers is the best method in general. Headspace gauges are advanced. Just don't go over the OAL and your OK. Don't need any other legnth specs. Just remember that the longer the oal the higher the pressure. The shorter the lower pressure. Same goes for the charge weight. Less powder equals higher pressure.

GioaJack
04-12-2010, 17:34
Measuring using calipers is the best method in general. Headspace gauges are advanced. Just don't go over the OAL and your OK. Don't need any other legnth specs. Just remember that the longer the oal the higher the pressure. The shorter the lower pressure. Same goes for the charge weight. Less powder equals higher pressure.


Think you may have a typo and mistakenly got that backwards. It happens.

Jack

HarveyatPC
04-12-2010, 18:55
Modelflyer,
I like 4.6 gr of TG and the COL is 1.150 with Berry's 115 plated bullets. This works well in a stock glock and in my KMM comp. Glock. IF you have accuracy problems - check the crimp. I used way to much in the beginning. Measure the case wall thickness X 2 and add to the Diameter of the berry bullet. That's the thickness you need - more crimp well give you flyers - especially at 20 to 25 yds. targets.
Harvey

Bamamedic
04-12-2010, 19:25
Think you may have a typo and mistakenly got that backwards. It happens.

Jack

No I don't have it backwords. Headspace guages measure your guns chamber not the cartridge oal. Headspace guages are for advanced reloading to set the cartidge oal to match the chamber.
For beginners just don't go over the listed OAL.

Bamamedic
04-12-2010, 19:31
I reloaded my first batch of 9mm, and I want your advice. I made 18 rounds of 115 gr. round nose, Berry plated, Hodgdon Universal 4.2gr, OAL 1.156. I arrived at the OAL after measuring one of my factory UMC rounds. I am not sure what OAL to set. They fit fine in my gage. Range report. I had one failure to chamber. When I dropped the magazine and ejected the round, I saw that the plating got scratched up in the process of chambering. I wondered if it failed to feed because of the OAL or possibly because the low charge (4.2 gr of Universal) failed to move the slide adequately enough. The other rounds worked fine. I am using the deluxe press from Lee and the dispenser seems to not be 100% accurate. I made another lot with the same diameter and powder charge and I will shoot them later this week. Should I change the AOL on them? I believe making them shorter will increase the pressure and the velocity. I donít own a Chrony. My Lyman 49th Ed manual gives only the Max OAL, and the Hodgdon data from the website does not give OAL either. What do you think?<!-- google_ad_section_end -->

I wouldn't use another round to determine the max oal. Use listed amounts in reloading books. Sounds like a gun problem not in the reloading unless the rounds were properly sized. I had a few do that. They were right at the cartidges max diameter. I use an aftermarket barrel and with rounds that were first shot in a Glock factory barrel. The factory barrel doesn't fully support the rounds which caused the case to bulge slightly at the base. With the tight match grade aftermarket barrel the round would not feed.

jbrown13
04-12-2010, 20:29
No I don't have it backwords. Headspace guages measure your guns chamber not the cartridge oal. Headspace guages are for advanced reloading to set the cartidge oal to match the chamber.
For beginners just don't go over the listed OAL.

I don't think Jack was referring to that part of your post, but rather your statements regarding the relationship of OAL to pressure and powder charge to pressure. These relationships do seem backwards to me as well.

XDRoX
04-12-2010, 21:33
Just remember that the longer the oal the higher the pressure. The shorter the lower pressure. Same goes for the charge weight. Less powder equals higher pressure.

Think you may have a typo and mistakenly got that backwards. It happens.
Jack

No I don't have it backwords. Headspace guages measure your guns chamber not the cartridge oal. Headspace guages are for advanced reloading to set the cartidge oal to match the chamber.
For beginners just don't go over the listed OAL.

Shorter rounds create lower pressure? Less powder equals higher pressure? I think Jack was probably referring to this.

modelflyer2003
04-12-2010, 22:29
Modelflyer,
I like 4.6 gr of TG and the COL is 1.150 with Berry's 115 plated bullets. This works well in a stock glock and in my KMM comp. Glock. IF you have accuracy problems - check the crimp. I used way to much in the beginning. Measure the case wall thickness X 2 and add to the Diameter of the berry bullet. That's the thickness you need - more crimp well give you flyers - especially at 20 to 25 yds. targets.
Harvey
Thanks for your advice. On Friday I made 20 rounds Hodgdon Universal 4.5gr OAL 1.135 Berry 115gr. They worked Flawlessly. In fact is one of my better trips to the range. I am still using the stock Glock barrel. I have heard not to crimp the Berry Plated rounds so that is what I have been doing.

Bamamedic
04-16-2010, 15:01
I don't think Jack was referring to that part of your post, but rather your statements regarding the relationship of OAL to pressure and powder charge to pressure. These relationships do seem backwards to me as well.
Oh! I see.
Yes it seems backwords, but it's true. The more room in the case either from less powder or the bullet not seated in as far, creates higher pressure. Don't get that confused with more power or force. Force and pressure are two different things.
The more air/oxygen in the cartridge is what creates the higher pressure.

Bamamedic
04-16-2010, 15:09
Oh! I see.
Yes it seems backwords, but it's true. The more room in the case either from less powder or the bullet not seated in as far, creates higher pressure. Don't get that confused with more power or force. Force and pressure are two different things.
The more air/oxygen in the cartridge is what creates the higher pressure.

Well crap! Now that I researched what I said, I am getting conflicting results. Some say the exact opposite of each other. One reloading book states that the more room in the case elevates the pressure and the other book says the opposite. DAMNIT!

Oh well! Just load within listed values and youll be alright.

Colorado4Wheel
04-16-2010, 15:11
Thats not true. As the case grows pressure goes down. As it shrinks pressure goes up. Thats why bullet setback can create massive pressure spikes leading to blown up guns.

PCJim
04-16-2010, 15:22
Bamamedic, you've "seen the light".

For a given powder charge using the same bullet, shortening the COL will reduce the case volume and increase pressure. Similarly, lengthening COL will increase case volume and decrease pressure.

That being said, oftentimes when the COL is reduced, the powder charge is also reduced. If changing both variables (COL and powder), then yes, it is possible to have a reduced cartridge pressure.

I'll edit this response to add: If you reduce the powder charge enough, it is possible with some powders to create a pressure spikes. This phenonomon (from what I understand) has never been reproduced in a laboratory setting. It is believed that the extremely small amount of powder is ignited at both ends of the powder, resulting with a detonation of the powder instead of a controlled (albeit uberfast) burn. Be very cautious if developing loads below published starting charges.

GioaJack
04-16-2010, 15:26
Well crap! Now that I researched what I said, I am getting conflicting results. Some say the exact opposite of each other. One reloading book states that the more room in the case elevates the pressure and the other book says the opposite. DAMNIT!

Oh well! Just load within listed values and youll be alright.



Baramedic:

Not to worry, not to worry... this stuff can be confusing if you're not used to it. In your reading of two sources they may have been referring to two separate things that occur under similar circumstances.

All things being equal, same power, same charge, same bullet weight, etc., the deeper you seat the bullet, (the less space between the base of the bullet and powder charge) the higher your pressure will be.

In a totally different vein but one that becomes confusing to some is a phenomenon known at 'detonation'. This has the potential of occurring when a very small powder charge is used, the ignition of the primer fails to cause ignition of the powder in a designed burn but rather builds up heat over time, (milliseconds) and instead of igniting the powder 'detonates', or in other terms, explodes, causing a massive and potentially dangerous pressure spike.

A very small amount of powder that is subject to 'detonation' can totally destroy a gun... or worse. Although many light loads can safely be developed that are below published minimums they should alway be approached with due care and in the opposite way max loads are developed... lowering the charge in very small increments.

Stay within published specs, either minimum or maximum and maintain reasonable OAL's and in almost every case the loader will have a pleasant shooting experience.

Jack


RATS... PC beat me to it... why the hell aren't you at work?