I'm a newbie loader.

I used a Lyman loading manual which had the max load for w748 and 55 gr jacketed SPT at 27.8 grains.

I used 26.8 grains.

I loaded 40 rounds and went to the range and they seemd to shoot fine. I don't see any obvious over pressure signs, but haven't seen any pic of what exactly to look for.

I called the load good and made another 160.

Then I start searching around arfcom today to find an answer to a loading problem I ran into and find some links and find the winchester manual online that says 55 grain bullet and W748 max load is 26.3. Oops. I loaded 26.8 which was 1 grain below max in the Lyman book. However both sets of data are for 55 gr SPT, I am using winchester 55gr FMJBT. I'm sure that makes a difference, I just don't know which way. higher or lower presure than SPT.

I know I jumped in with both feet and didn't work my way up in loads. I thought I had picked a middle load to plink with. Now I find I might have exceeded the max load.

I am loading to practice with and want a good safe load that i can reuse my brass a lot. It's all various stamps.



here is my question I can't find any pics on what to look for for an overpressured round. maybe I just got lucky with the first 40 rounds, but I don't see any obvious signs of case failure, no splits, rings or bulges.

I think my best bet is to pull the bullets on the 160 rounds I have made and reload them to 26.0 grains. or better yet start at 25.0 and look for my best accuracy up to 26.3

Sorry for the long ramble, it's 0230 and I'm tired.

thanks for any help

Loading data varies greatly in .223 Rem because most pressure tested data is done in a SAAMI chamber/throated barrel.  If you use this dara in a NATO chamber/throat, pressure will be lower.  So you are probably safe.

The REAL pressure sign will be loose primer pockets.  Or pierced primers.  Don't think you have to reach these levels because you may not reach these safely.  And because expanding primer pockets indicate yielding of the brass, there is NO SAFETY.  You may get away with it for 20 rounds but will that 21st round have adequate strength?  Don't guess, that extra 50 FPS don't make a damn difference if you have to replace a bolt every 100 rounds.  Even a firing pin is $12.

Your 26.8 grain load should be safe in your AR-15 with Win 55fmj's using Win 748. I've shot them at that level and higher with no signs of high pressure in an AR. However when also trying the higher level loads in a bolt action rifle in hot summertime temperatures I did get very high pressure signs. Winchester 748 is reported to be temperature sensitive and pressure goes up in high heat. My complaint with reloading manuals is they usually test data using a bolt action rifle. One manual says 26.4 grains max. while another says 26.5 max (in AR's) while some data goes up to 27.7 as a max. My testing using RP, LC, WCC ,and Win cases and RP 7 1/2 primers led me to settle on 25.9-26.4 grains of 748 using Win or Hornady 55 fmj's. At that level it showed no high pressure in my bolt action rifle.
  I wouldn't pull down your 26.8 grain loads but would only shoot them in an AR. Flattened primers, rings forming around the firing pin indent where the primer tried to flow into the firing pin hole, pierced primers, and loose primer pockets in your fired rounds would indicate high pressure. I have most all the manuals available and compare data from all sources plus powder company data on the net. Also  I use a chronograph to check velocities.
 Again, my tests show that 26.8 grains of 748 in an AR with Win 55fmj's would not show high pressure. However my loads at 26.1-26.4 shoot fine and the 26.4 load shows the best accuracy in a couple AR's. That level is also easier on brass. I have loaded and shot a lot of loads using 748 and Win 55 fmj's but have long since switched to Hodgdon H335 and Hornady 55fmj's. I get better results, and higher velocity with 55 fmj's using H335.
  You shouldn't worry about your 26.8 grain load in good brass. Some report using higher charges than that but I would drop down to 25.9 and work up to 26.4 looking for accuracy gains. At that level you would be ok using any brass I've ever loaded.

You need to review a good reloading manual, oops that might mean spending money rather then trolling on the internet, they all have sections on signs of pressure such as sticky extraction, primer flattening, primer piercing, loose primer pockets, case head expansion.  Sit down and read, not troll!

Reel it in, please.  The load manuals do not have really good, or complete and thorough, write ups about interpreting signs of pressure.  The internet is not much better, but there are gems here and there.  We should work harder to get that lack of information corrected here.  AeroE

i agree with all the above info everyone gave MACH for high pressure signs to look for execpt for loose primer pockets as signs of high pressure. i have some once fired FC .223 brass and in seating cci400 primers alot of them almost fall in,feel real loose. also loose pockets could be the brass has out lived it's usefulness.jim

Why is his question trolling?  Why do think he's not trying to gather as much information as possible, both by reading books, and by asking for informed opinions from people on an internet forum that is directly involved with the topic?  Why do you think the internet can't be a source of good information?  And lastly, why do care enough to insult the guy, but not enough to offer your opinion on his question?

It's his standard response.  See?

I did. I spent 4 hours last night looking and I thought I had a good reloading manual and read every tacked thread and searched for others. I found some signs and even found a pic of what primer peircing is but never found what case head expansion, or primer flattening looks like. Didn't know asking questions I can't find the answers too was trolling. Next time you have some questions on defensive handgun use, DT, flying a fighter or commercial airliner, fly fishing, rock climbing, ice climbing, how to prepare long term food storage, how air to air missles work or airplanes on a treadmill, let me know so I can call you a troll.

Reading primers ain't the only way.....but, here are some pics........

http://www.radomski.us/njhp/cart_tech.htm

(about half way down the page)

And……….

http://stevespages.com/diagnosingproblems.html
__________________

BTW, most books will have this warning (or similar warning)………



Aloha, Mark

PS............there are many more reloading WARNINGS........read your manual.  And, take heed of the WARNINGS.  Before something bad happens.

Thank you for all the help.

At first after reading the links suggested I thought I had some primer flattening, but after some macro pics, i don't see any sign of overpressure on the primers or anywhere else. It does make me nervous though since I am using more than a max load in one of the books, but 1 grain less than another book and mostly military brass which will create more pressure due to thicker brass than civilian, plus I'm using CCI 400 primers, not RP 7.5 that RG1 said that he was using.

I picked all my components based on price. Win 55gr FMJBT for $90/1000, W748 for $19/lb, and CCI 400 primers cause that's what the shop had and the beass once fired by me. All in all I have enough to load 4000 rounds. I have factory ammo for long term storage, this stuff is for practice and drills for CQB self training.

Like most things I jumped in with both feet and didn't learn enough first. Now I just have to decide to pull the 160 rounds I have left of the 26.8 grain loads. I'm leaning towards no, but may change my mind so i can sleep better.

I am going to back it down some and make different loads looking for best accuracy out of my 6920. Thanks for all the help.

what an ass

Those primers look OK, no flatening, no ejector marks, still has a radius, no creatoring, no melted look around or in the pin indent.
Looks like they're medium pressure for your rifle.
'Borg

Good information here  and here. Got  those links from this link.

ETA: Thank God for the internet and all those who share the research.

Your pictures shows no classic signs of pressure. Shoot your loaded rounds. Didn't see any sign or the horseshoe shaped ejector marks on the case heads either which also is a good indicator of pressure.