Help with high pressure loads.

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Luis1

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Ok I had an interesting day today at the range. I was testing a ladder for a load I was developing.

Stag 10 - 18.75 inch - factory built
308 win
Hornady brass
H4895 powder
CCI primers
Hornady ELD-M 168GR pills

Ladder
42.5gr, 42.6gr, 42.7gr, 42.8 gr and 42.9gr

Min load - 41 gr
Max load - 43.5gr

I started my ladder and right away I had extreme high pressure signs - indentations from the ejector and blown out primers (majority had this) - there was lots of soot on my rounds in the magazine and a little smoke was seeping out of the magazine and the ejection port. I tried a couple from the other batches and got the same results - velocity ranged around 2700.

Two of the rounds were jammed in the chamber (one was really bad and took a second person to help motar it out). I checked these in a chamber gauge and the headstano on these two rounds were about 1/8th below the acceptable range.

I ran a few rounds of 168 gr hornady Tap factory ammo and got the same results - 2 rounds had some pressure signs and 3 had blown out primers.

I ran several rounds of my plinking loads - 147gr pills over 42gr of h335 - these had no issues and no pressure signs at all.

I took the gun apart and (aside from pieces of primer that fell out of the bolt) there was no issues. Only thing I found was they the firing pin retaining pin was bent about 45 degrees. Headspace was checked and there was no issues there.

I checked the rounds I had left when I got home and noted that none of the charges were thrown incorrectly.

I am stumped on this one.. Please help me figure it out. Thanks
 
Nope - h4895 load data

I wouldn't be so concerned with the above if it was just involving handloads, but it did the same thing with factory ammo. That does worry me a bit.
 
Yup have been loading it from the start. I have two developed loads for it all ready that cycle with no issues. One with the same bullet, but imr 4895 and one with 147gr campro and 42gr of h335. All other factory ammo cycles with no issue up until now (as far as I can tell). I brought it to a Smith and headspace was checked and all was good. So I'm just hoping that my particular rifle doesn't like that particle combination of powder and seating depth with bullet weight and that the factory ammo was just plain bad.

If anyone has any insight please pass it along. I will continue to load for this rifle, I'm going to start just below min loads and work up from there and see what happens.
 
I can't see that being an issue? I would have a very short chamber otherwise? I am going to post this in the battle rifle thread for the factory ammo issue.
 
The Hogdon site lists 39-min and 43 as max with H 4895. If this is your first time using this powder it could be easy to think that 42.5 grs ,where you started, could be over pressure. Just throwing this out.
 
This is a good point I never thought of it that way. When I did shoot these I did so over a chrono as well and it was 2680 to 2730 for the rounds I shot. Out of an an 18.75 inch barrel I figured that this was pretty high.

I just want to know why this is happening with factory ammo too though.
 
Just throwing out a few ideas. Neck tension. Did the bullets take a lot of force to seat on your press?

Could you be jammed hard into the lands? Perhaps your rifle has a very short throat.

Since it happens with factory 168 grain ammo but not 147 grain handloads my suspicions are you have a short throat and have the bullet jammed into the lands.
 
Hogdon never got that vel with a 24" barrel. Their max vel with the 168 Sierra was 2707 ft/sec. The factory thing is a puzzle though. Have you shot much factory in the past in this rifle.
 
Just throwing out a few ideas. Neck tension. Did the bullets take a lot of force to seat on your press? no not really, but they were difficult to pull out when I broke the rounds down

Could you be jammed hard into the lands? Perhaps your rifle has a very short throat.

Since it happens with factory 168 grain ammo but not 147 grain handloads my suspicions are you have a short throat and have the bullet jammed into the lands.

I thought this too, but my other rounds which use the same bullet and same seating depth and trim length, but use Imr 4895 have no issue
 
Is it possible that these rifles could be suceptable to pressures that are normally not considered hot? Do modern rifles like that exist?
 
Luis1 said:
Is it possible that these rifles could be suceptable to pressures that are normally not considered hot? Do modern rifles like that exist?
Click to expand...

Can't say that I know of any rifles that are specificely designated to be like this, but I own over 20 rifles and with some I can surpass the book max, but in others pressure rears it;s ugly head before I get there. Some rifles well before. My 300 Win mag is one in particular.
 
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I've built up a load with almost exactly the same components. I can't remember offhand but I was getting pressure issues way before the max load. I think I settled at 41.3 for cold weather. I'll look at my book tomorrow when I'm home. It is why they say start at min and work up.
 
Thanks cartwheel. I think I'm going to chalk this up to me misreading the manual as hunter home suggested. Hard lesson learned here. Now if only I could figure out why the factory loads were doing this, and why several of the rounds had shortened shoulders after chambering..

I have also been reloading with a FL sizing die for 308 I have read on other forums that I should be using a SB sizing die, do others do this?
 
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I could be wrong on this but

I think H4895 was / has been made in different factories / different countries

on the back of the can where was the powder made ?

data for the different factories will be different

start low and work up ... is the standard

even powders from the same factory / different lots // can vary by over 5%
 
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