Author Topic: Pressure signs,bad! (Read 1071 times)

stillhunter · « **on:** August 17, 2003, 06:17:19 PM »

:x :oops: Help, I need advice. At the range today, shooting a load that has been fine all summer I had a case fail to extract. Upon removing the case with a rod I saw what I have read about but never seen before :shock: The primer was flattened and brass flowed into the ejector hole in the bolt face. The base of the case was crooked. Needless to say I quit shooting. I intend to pull apart the remaining loads and recheck things, including my scale , aol, die settings etc.. Any hints as to what to do aside from backing off a grain or too.

Gun BLR81 .308
165 Sierra BT
Reloader 15 46 Gr
Fed Brass 3rd fireing
Fed 210
2.80 aol

Thank in advance .

ringo · « **Reply #1 on:** August 17, 2003, 06:38:09 PM »

What was the temperature at the time of shooting? Was your ammo sitting in the sun (vehicle or shooting bench) taking on heat? Did you weigh every load prior to reloading or spot check every 5th one? Is your scale working, sometimes balance beam scales "stick" and over charging can happen? Do you use small base dies on your BLR, might be a volume problem (smaller volume = hot load), after how many rounds do you clean your bore? Is there a recall on your powder batch, maybe there should be.

CJ · « **Reply #2 on:** August 17, 2003, 06:42:15 PM »

Possible bore obstruction? That can raise pressures fast. do you have other powders on hand that could be mixed up?

John Traveler · « **Reply #3 on:** August 17, 2003, 07:00:18 PM »

A few other things to check for:

1. case trim length. Over-length cases "pinch" the bullet, and can skyrocket chamber pressures.

2. bullet diameter. I once mistakenly loaded .311 bullets into a .308 cartridge. What a MISTAKE that was! Blown primer, failure to extract, everything!

3. wrong bullet weight. Any chance a heavier bullet accidentally got into your 165 grain boattails? Sierra makes several similar, heavier, bullets in .30 caliber.

4. wrong powder/too much powder?

Jack Crevalle · « **Reply #4 on:** August 18, 2003, 01:08:12 AM »

Change anything? Even new batches of the same type/brand primer, powder, bullet?

Did this happen on the first round or did you fire others sucessfully? How
did the brass from those look?

Switch cleaning supplies or methods?

John Y Cannuck · « **Reply #5 on:** August 18, 2003, 01:30:34 AM »

Scary part, is it may have been a one off. One error, and if that's what it was, you will not find a problem anywhere. But it will drive you absolutely crazy trying to figure if you've checked everything.

Savage · « **Reply #6 on:** August 18, 2003, 02:44:22 AM »

My Hornady manual lists 42.2grs of RL-15 as max with the 165gr.(Yikes!!!) Recheck your load data before you fire any more of this recipe!!!! If you don't have a Sierra AND a RL manual GET ONE! The BLR is a strong action, much akin to a bolt gun in the lockup, but I'd stay away from max loads.
Good Luck,
Savage

The Shrink · « **Reply #7 on:** August 19, 2003, 05:38:16 AM »

STOP! Don't use that load again!

Sierra Manual #5 lists 43.1 gr of RE 15 as their Max load for their 165 grain bullets in the .308. At 46 grains you are way off the mark. If at all possible, always use the bullet manufacturers data when approaching max loads, because it is the variable of the bullet design that makes the most difference. Their max load of 43.1 gr should give you around 2700fps, depending on atmospheric conditions.

PS Sierra lists AA-2495 at 40.4 grains as thier accuracy load, and Viht N550 at 45.2 as the recommended hunting load.

Ron T. · « **Reply #8 on:** August 19, 2003, 03:03:38 PM »

Assuming Waynes (the Shrink) information is correct, your load of 46.0 grains of RL-15 is almost 3 grains over the maximum charge. You are nearing the blue pill load at which point things start coming apart.

Youre VERY, VERY fortunate that Browning makes good rifles and that the Good Lord was looking over your shoulder.

Whats significant and really SCARY is that brass was FLOWING into the ejector hole in your bolt-face and the base (the strongest, thickest part of the cartridge case) was bent and distorted. When the brass flows like that, the chamber pressure is HUGE VERY close to exploding!!!

YOU ARE ONE VERY LUCKY MAN, MY FRIEND!!!!!!!!!!!!!!

I strongly recommend you buy a good reloading manual and READ it from cover-to-cover cause its obvious you dont have one. I know this because no reloading manual would recommend any load that was 2.9 grains over the maximum load given by the bullet maker (Sierra) and 3.8 grains over the much respected Hornady Reloading Manuals maximum load.

You should go kick the crap outta the guy that gave you that load! :blaster:

Ron T.

John Y Cannuck · « **Reply #9 on:** August 20, 2003, 01:03:24 AM »

From "Steves pages"
RL-15 From 35.2 grains to 47.0 grains listed for the 165grain in 308Win.

Now Steve can sometimes post some pretty hot stuff, but I don't think he'd post all that high.

John Y Cannuck · « **Reply #10 on:** August 20, 2003, 01:06:22 AM »

On the other hand, this is from Alliants site listing for the Sierra 165SP
Fed. 2.700 OAL, 24.0bbl, Fed. 210Primer, Reloder 15, 45.5gr, 2,780fps 57,000pressure

John Y Cannuck · « **Reply #11 on:** August 20, 2003, 01:10:58 AM »

My wife's Browning has a distinct distaste for anything aproaching max loads. It likes it closer to minimum loads. It has a "tight" chamber, or so the Browning service guy says.

Savage · « **Reply #12 on:** August 20, 2003, 05:13:32 AM »

Gotta remember that the loads that appear in "Steve's Pages" were worked up in another rifle using most likely a different lot of powder and compotents under different atmospheric conditions. There is NO reason to start out ANYWHERE near max loads when working up a load. The bullet manufacturers perform a lot of extensive research and testing. The powder manufacturers do the same. I would highly reccomend using their data, and starting out AT LEAST 2 grs under the max load. When you get up near the max the old "Law of Diminishing Returns" kicks in. There is very little velocity gain in relation to the pressure rise. Getting your loading data from a friend, or a friend of a friend, and especially the Web is very dangerous.
Stay Safe,
Savage

John Y Cannuck · « **Reply #13 on:** August 20, 2003, 06:05:30 AM »

I've seen Steve queried about his loads before. Basically, he'll tell you that you should be reading a reloading manual, using his loads as a guide to a possible max only, and working up.
The language he uses may be somewhat more colourfull. :eek:

Guybo · « **Reply #14 on:** August 20, 2003, 07:22:07 AM »

I really don't have anything to add, i agree with everyone else here, you're a lucky guy! Get yourself a good load manual and while your at it give one to the guy who loaded those bullets for ya, man thats dangerous! Mike

stillhunter · « **Reply #15 on:** August 21, 2003, 02:31:08 PM »

Thanks for the input all. Since I did not have a Sierra manual I did use data from other places ie Alliants site, Steves pages and others. Also I did work up slowly .5 gr at a time from 42 gr and never saw a hint of pressure. Be that as it may I am obviosly past any kind of safety margin. I scrapped all the brass from the hot loads and will start over with better data.

Thanks again.

Muddyboots · « **Reply #16 on:** August 21, 2003, 03:50:10 PM »

Hate to throw more rain on the parade but I strongly suggest taking the rifle to a gunmith who can take a good close look at the metallurgy of the receiver. Pressure like your rifle went through may have damaged the receiver. Steel is no different than any other material. Once you past the point of elasticity of the steel, the structure is altered. Brass flowing is a significant indicator of extremely high pressure (you were way beyond a basic flattened primer) and you are more than lucky to still have all your appendages and eyesight. High pressure loads damage receivers, those who think the rifle "can take it" are only setting themselves up for a catatrophic failure. Every time you stretch the receiver with a high pressure load, you are weakening the crystalline structure of the steel. I hope you will consider this suggestion since the next "mild" load can still fail due to a weakened receiver. Good luck.
Muddyboots

rickyp · « **Reply #17 on:** August 21, 2003, 03:57:16 PM »

the hornady 4 th edition reloading handbook showes that 42.2 is the max load for what was listed. if you ( or anyone else) need loading information shoot me a pm and we can work something out. I WILL ONLY GIVE OUT WHAT IS PRINTED IN THE BOOKS /software

T/C nimrod · « **Reply #18 on:** August 22, 2003, 02:40:21 AM »

Quote from: Savage

There is very little velocity gain in relation to the pressure rise. Getting your loading data from a friend, or a friend of a friend, and especially the Web is very dangerous.
Stay Safe,
Savage

Savage, In my quest to fully understand pressure, and the dynamics of pressure, I found an interesting article on pressure vs. velocity. I'll quote verbatum when I have it in front of me, but the data showed a round (.270, I believe it was) pushing 2485 fps @ 47,000 PSI (PSI vs. CUP, CIP is another discussion) and the same rifle pushing the same bullet at 2485 fps @ 52,000 PSI. It was interesting to compare this data to my findings. I guess the point I'm trying to make is that if any components are changed, you can't use velocity readings to assertain what pressure you are at. This information was found in Modern Reloading, second edition in the sections on pressure (Chapters 8-10). If I remember correctly, this was data relating to cast bullets, so I'm also not sure if it applies to jacket bullets. I'm being very humbled in learning how much I thought I knew, and how much I truly understood.

You nailed it about where one gets his/her loading data from. Reloading manuals are considered the "safest", but even the printed data can be wrong (a typed 5 instead of a 1)

Savage · « **Reply #19 on:** August 22, 2003, 09:17:24 AM »

T/C,
Exatcly! The max in one rifle may not be (and usually isn't) safe in another. That's a good reason to read the realoading manual. It's hard to miss all the disclamers and admonishments to start below the published max and carefully work up untill you reach your rifles max load. Your rifle's max may be well below the published max load in the manual. Of course when you change any compotent----------well, better start out low and work it back up again. I have found no advantage in shooting max loads in anything I have loaded for in the last 35 yrs. Your most accurate loads are usually well below max. Not to mention how much easier on the shooter and equipment they are!
Stay Safe,
Savage

Lee D. · « **Reply #20 on:** August 22, 2003, 09:51:00 AM »

Savage,
I agree about using max loads. I have several rifles I load for (.348,300sav,6.5X55,.308,etc) As an example I load my .308 for a micro medallion at 300 savage velocity with a 165 grain bullet. It kills anything I hit, very easy to shoot, and my brass lasts just about forever. When I get out west Elk hunting I buy a box of one of the "light magnum" loads, resight for them and off I go. They are no where near as pleasant to shoot!