Palma Brass at 76000 PSI

[APGE]

Hi Folks,

I've recently worked up a load for my 17 twist 308 shooting 118 BIBs. I'm using Palma brass and a stout load of H322. I got my starting load from Quickload and worked up from there. The first pressure sign I got was a pierced primer at 49.6gr. No firm bolt lift, no ejector swipe, just a pierced primer. The action is a Rem 700 and the firing pin hasn't been turned down and bushed, so I blamed the factory bolt.

Anyway, I got a load that is an absolute hummer at 48.7gr. I'm talking repeatable sub quarter minute 5 shot groups and spectacularly good elevation out to 600 yards. I figured I'm nearly a full grain under where I pierced a primer, so I had some factor of safety.

I ran the load through quickload just now out of curiosity - the calculated pressure was 76000 psi!

Now I'm not advocating this by any means. If anything I'm a little worried.

However - I have nearly 200 rounds through the rifle at this loading. Cases are not clicky and I have some that have seen 4 loads and have not needed a full length sizing. Primer pockets certainly aren't super tight, but are holding primers fine.

I have heard of some Aussie FTR shooters loading up at similar pressures, but this still has me wondering if I should try and find a lower node. I'm reluctant to do this though because the one I have is so solid.

Any advice? Is my slow twist barrel and short bearing surface bullets keeping pressures lower than quickload calculated?

 

[Ggmac]

Hi Folks,

I've recently worked up a load for my 17 twist 308 shooting 118 BIBs. I'm using Palma brass and a stout load of H322. I got my starting load from Quickload and worked up from there. The first pressure sign I got was a pierced primer at 49.6gr. No firm bolt lift, no ejector swipe, just a pierced primer. The action is a Rem 700 and the firing pin hasn't been turned down and bushed, so I blamed the factory bolt.

Anyway, I got a load that is an absolute hummer at 48.7gr. I'm talking repeatable sub quarter minute 5 shot groups and spectacularly good elevation out to 600 yards. I figured I'm nearly a full grain under where I pierced a primer, so I had some factor of safety.

I ran the load through quickload just now out of curiosity - the calculated pressure was 76000 psi!

Now I'm not advocating this by any means. If anything I'm a little worried.

However - I have nearly 200 rounds through the rifle at this loading. Cases are not clicky and I have some that have seen 4 loads and have not needed a full length sizing. Primer pockets certainly aren't super tight, but are holding primers fine.

I have heard of some Aussie FTR shooters loading up at similar pressures, but this still has me wondering if I should try and find a lower node. I'm reluctant to do this though because the one I have is so solid.

Any advice? Is my slow twist barrel and short bearing surface bullets keeping pressures lower than quickload calculated?

Advice = buy your self an insurance policy ! And a lottery ticket .
I'm glad it's working but I'd find a lower point . After all , it doesn't last forever.
Let me rephrase that , next time you go shooting , try shooting with the eye you don't use . Just in case you have an accident and lose your dominate eye .
Unfortunately I've seen it happen , and yes he has glasses on . Not a pretty sight. No pun intended.

 

[spclark]

Is my slow twist barrel and short bearing surface bullets keeping pressures lower than quickload calculated?

Be my guess yes, but....

A well-respected long range shooter I know uses Palma brass with 155 Hybrids in slow-twist, low land height barrels with loads other folks cringe thinking about.

Hasn’t blown one up yet.

You feel comfortable working up around those pressures?

Ever hear of a system called Pressure Trace? I bought a kit a few years ago when working with a 7mm wildcat for evaluating loads. Worked great. I don’t use it anymore, you can have it for less than I paid for it, shipping paid for.

Confident in your health insurance carrier?

It’s certainly a personal choice to explore the fringes. When I worked as a railroad brakeman the catchphrase was “Safety First, Last, Always.” My personal choice is to apply that to my shooting pursuits also. Something goes south it’s the other guys picking up the pieces.

 

[ShootDots]

I can tell you this: The Lapua S/R Palma brass is as strong as an M1 Abrams tank! However, even though it can handle "excessive" pressures compared to L/R primed brass, the question remains "should it be done"? It has been MY experience that when you shoot at very high pressures, you are at the TOP of the HIGHEST node you can possibly shoot. Generally, when you are "up there": 1.) barrel life is shortened considerably compared to "normal" pressures; 2.) that HIGH node usually has a very "tight" window of accuracy; 3.) something that is normally overlooked: The hard carbon build up can really become difficult to remove or even control.. These are some things to consider when running such pressures..

 

[243winxb]

Looks like bullet bearing surface and construction is the key factor? Photo is of the highest published load i could find. Other data is about 3 grs less powder.

Hodgdon & SAAMI photos.


What kind of velocitys are you recording? Added - your barrel length?

 

[clowdis]

The Lee Reloading book lists a maximum load of 45gr. of H322 for a 125 gr. bullet, so you're 4.6gr. over the max. recommended load. That's a pretty fair amount over and on a powder that is temperature sensitive. It could bite you at the most inconvenient time.

 

[Shrek]

If it’s working in your rifle it’s working.

 

[243winxb]

Very small bearing surface on this all copper Barnes bullet.

Note the difference in powder charge between Hodgdon and Barnes data, same bullet/powder.

 

[Laurie]

I ran the load through quickload just now out of curiosity - the calculated pressure was 76000 psi!

How does the QL calculated MV compare to the actual? If actual is significantly different, either way, from estimated, then the calculated pressure will almost certainly be out too.

I've run a lot of other people's loads and (claimed actual) velocities through QuickLOAD for small cartridges that use the small primer and flash-hole, and if people's chronographs / records are accurate (big if sometimes) then either QL is at times really wildly out or they are routinely running >70,000 psi, in fact often way, way over that figure. This was most common IME amongst 6.5X47L field shooters, but with the arrival of SRP/small flash-hole 6mm and 6.5mm Creedmoor brass, I'd imagine it now applies to them also.

We know that these cases are very, very strong and will survive multiple firings at pressures that send equivalent LRP alternatives to the scrap bin on their first firing, but I occasionally wonder if it is simple robustness or the SRP / small-flash-hole arrangement changing basic ignition behaviours and flattening the peak at the beginning of the time / pressure curve, or the two in combination.

 

[Laurie]

Note the difference in powder charge between Hodgdon and Barnes data, same bullet/powder.

Compared to many combinations published by different data sources, I'd regard 0.9gn difference as modest - under 2%. Different makes of brass / primer models alone will often produce larger differences, but if your Barnes manual uses Winchester brass and the F210 as mine does (but which lacks data for the 110gn bullets), then in this comparison both use the same case and primer make (albeit different primer models as in F210 and F210M).

So, assuming both companies adopted identical recorded pressures for their maximum recommended loads - by no means certain - a 1.9% variation comes down to minor variations in component lots, possibly differences / tolerances between Hodgdon and Barnes pressure recording equipment / testing methods, and variations between the internal dimensions of the barrels used in pressure testing. As always, maximum loads are at best a guide.

 

[APGE]

Thanks for all the replies, folks. I did some head scratching trying to work out how I ended up so high. Initially I was jumping bullets, but ended up with a light jam during load development.

Using the jump start pressure (3626 psi), QL comes in at a much more sensible 65000 psi max. Changing the shot start pressure to 10826psi, I end up with the 76000.

Perhaps the fact that I only have a light jam means my real shot start pressure is a bit lower than the QL recommended one.

I'll try and run them over a chronograph on the weekend and see how fast I'm going.

 

[Laurie]

Using the jump start pressure (3626 psi), QL comes in at a much more sensible 65000 psi max. Changing the shot start pressure to 10826psi, I end up with the 76000.

It's never wise to be too definitive about anything in this game, but I learned a long time ago to either leave the default start pressure untouched for mild bullet seating in the lands or at most apply a small increment to be on the safe side. We also know that as Joe R says, QL takes no account of primer power, but as a general rule you need anything between 0.5 and 1.5gn heavier charge in 308 Palma to obtain the same MV as from 'regular' LRP Lapua cases with the same water capacity, the exact amount depending on the bullet and powder grade used.

 

[David101]

There may be some FTR shooters shooting loads that are at the same pressure as you. However I bet they are using a Barnard action which make the Remington action look like a toy. They would also have a barrel that is 1.25 inch around the chamber area and forward of it. All that gives them some safety margin with a Remington it could let go at any time putting the bolt through your eye.

 

[APGE]

If you are jamming your bullet, I believe the QL manual says something about a shot start pressure of around 7,200 psi and even that is an initial guess that has to be adjusted once you get actual data. The 10,826 seems way high.


Joe

I always read it as ADD 7200psi to the shot start pressure when jamming (ie 3626+7200 =10826). Have I been doing this wrong for years?

 

[Rsadams]

My advice is , if you're an experienced reloaders and something doesn't feel right or worries you... Stop... Your guts usually correct.... I wouldn't take chances on missing fingers , eyes or your life or on the lesser side , destroyed brass or rifles... Over the years I have learned a screaming hot round isn't necessarily an accurate one..

 

[Murray Brook]

I always read it as ADD 7200psi to the shot start pressure when jamming (ie 3626+7200 =10826). Have I been doing this wrong for years?

That is what it reads and how I have been doing it. Don't forget to adjust your weight factor as this will affect pressure as well.

 

[Ned Ludd]

SAAMI spec for .308 Win is 62,000 psi. Palma brass is certainly very strong and can take much higher pressure than standard .308 Win brass. But the real question is why run the pressure that high, especially with such a fast-burning powder? Even in light of the potential discrepancies with pressures predicted by QuickLoad, 76K psi is just stupid hot. Why risk it? I find it hard to believe you can't find an equally good node at slightly lower pressure.

 

[243winxb]

What the firearm is telling the shooter vs Quickload , i would believe real world results. https://www.accurateshooter.com/gear-reviews/test-quickload-review/

WARNING: QuickLOAD is a computer simulation of centerfire cartridge performance. YOU MUST NEVER just “plug in the numbers” and use QuickLOAD’s output for a load recipe. That is foolish and dangerous. There are many reasons why the data QuickLOAD generates may not be safe in YOUR gun. Before loading live ammunition, you should always check with the powder-makers’ most recent load data. In fact, you should check multiple sources if possible, and consult with individuals who actually load for that cartridge. Sierra Bullets offers free load maps which, in general, are fairly conservative. Even when using manufacturers’ load data, start 10% low and work up. Differences in brass, primer brand, and seating depth can make huge differences in pressure. Always reload conservatively and always double- and triple-check QuickLOAD’s output against reliable load data supplied by the powder-makers.

I like this.

 

[Ggmac]

Hi Folks,

I've recently worked up a load for my 17 twist 308 shooting 118 BIBs. I'm using Palma brass and a stout load of H322. I got my starting load from Quickload and worked up from there. The first pressure sign I got was a pierced primer at 49.6gr. No firm bolt lift, no ejector swipe, just a pierced primer. The action is a Rem 700 and the firing pin hasn't been turned down and bushed, so I blamed the factory bolt.

Anyway, I got a load that is an absolute hummer at 48.7gr. I'm talking repeatable sub quarter minute 5 shot groups and spectacularly good elevation out to 600 yards. I figured I'm nearly a full grain under where I pierced a primer, so I had some factor of safety.

I ran the load through quickload just now out of curiosity - the calculated pressure was 76000 psi!

Now I'm not advocating this by any means. If anything I'm a little worried.

However - I have nearly 200 rounds through the rifle at this loading. Cases are not clicky and I have some that have seen 4 loads and have not needed a full length sizing. Primer pockets certainly aren't super tight, but are holding primers fine.

I have heard of some Aussie FTR shooters loading up at similar pressures, but this still has me wondering if I should try and find a lower node. I'm reluctant to do this though because the one I have is so solid.

Any advice? Is my slow twist barrel and short bearing surface bullets keeping pressures lower than quickload calculated?

If your action / barrel nose relief is cut to spec and not overly large and your running a stock extractor , you SHOULD be safe . I would still look for a softer load .

 

[Webster]

Hi Folks,

I've recently worked up a load for my 17 twist 308 shooting 118 BIBs. I'm using Palma brass and a stout load of H322. I got my starting load from Quickload and worked up from there. The first pressure sign I got was a pierced primer at 49.6gr. No firm bolt lift, no ejector swipe, just a pierced primer. The action is a Rem 700 and the firing pin hasn't been turned down and bushed, so I blamed the factory bolt.

Anyway, I got a load that is an absolute hummer at 48.7gr. I'm talking repeatable sub quarter minute 5 shot groups and spectacularly good elevation out to 600 yards. I figured I'm nearly a full grain under where I pierced a primer, so I had some factor of safety.

I ran the load through quickload just now out of curiosity - the calculated pressure was 76000 psi!

Now I'm not advocating this by any means. If anything I'm a little worried.

However - I have nearly 200 rounds through the rifle at this loading. Cases are not clicky and I have some that have seen 4 loads and have not needed a full length sizing. Primer pockets certainly aren't super tight, but are holding primers fine.

I have heard of some Aussie FTR shooters loading up at similar pressures, but this still has me wondering if I should try and find a lower node. I'm reluctant to do this though because the one I have is so solid.

Any advice? Is my slow twist barrel and short bearing surface bullets keeping pressures lower than quickload calculated?

You don't seem to have any understanding of making safe ammo. My Berger manual gives 45.8 gr max load with H322 with a 115 gr bullet. You are 3 gr over this. Your Rem action was probabaly made to have loads under 65,000 PSI? Of course there is a big safety margin built in when they recommend a safe pressure but You stated yourself your at an estimate 76000 PSI, this is crazy. This wouldn't be a safe load in a custom action. Why are you shooting 118 gr bullets in a 308? Doesn't sound like a competition load.