Palma Brass at 76000 PSI

[rmr]

Also keep in mind that quickload makes pressure/velocity estimates based on a fixed set of variables. (a lot of variables) change the variables (or are incorrect to begin with), and the estimate will be incorrect.

I've recently run into a similar problem with the 500SW. the bullet I'm using was never intended for the 500SW (was built for the 50AE) and I'm working with a Bighorn89 at very high pressure levels. *QL estimated* ~65-68kpsi. The quickload velocity estimates -vs- pressure simply did not add up. for a given load/bullet/seating depth etc, the charge Wt is off by a full 3gn across the entire charge range. the trick is finding the variable that is incorrect.
I'm not concerned at all running hot in my case, as the BH89 is the strongest lever gun ever built, and like you, I have cases with 6 firings on them, tight pockets, fired cases are 100% in-spec and drop right into a empty chamber. I ran some test loads up into the *QL estimated* 75k range and while the performance was astounding, was a little too far out of my personal comfort range. at an estimated 75k, my primers were not pierced, but were starting to crowd the "a bit too flat" comfort level.

TLDR: quickload is an estimate. Chronograph your loads, and see where you are at. double check the bullet data in the QL database to make sure that it matches the bullets you have in your hand. verify that the case capacity of your cases matches QL. if after a chrono session, the charge wt/velocity seem to make sense, and you are comfortable with the risk...

 

[APGE]

You don't seem to have any understanding of making safe ammo. My Berger manual gives 45.8 gr max load with H322

What cases did Berger use? What was the twist of the barrel? What was the bore diameter? What was the cartridge overall length? What was the lot number of H322 used?

All these things will effect pressure. Part of the reason I posted this is that the loads have no signs of being over pressure. With different barrels on the same action I have stopped load development when I got a stiff or clicking bolt lift or an ejector swipe; I've seen neither of these things in this load. Quickload at predicting 76k psi, but I'm really not confident that that's what I'm making.

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

Remington make ultra mags and Lapua mags on 700 actions. The hoop stress and longitudinal stress in a 308 chamber at 76000 psi (assuming my load is indeed producing that) won't come close to a magnum running at the same pressure. The bolt lugs would still be experiencing a comparatively gently force.

Why are you shooting 118 gr bullets in a 308? Doesn't sound like a competition load.

17 twist bartlien, zero freebore. Very competitive for the bastardized hunter class benchrest my club runs that requires a minimum case capacity of 50gr h2o

 

[ebb]

If you are so confident that this load is safe why ask the question? And furthermore now that you have asked why all the arguing? If you believe it is safe shoot it. I know nothing of quick load, but have seen it described as the birth place of all bad ideas. If it is truly making 76000 psi it would show signs of pressure I am sure. But I would check closer an ejector mark and clicky bolt are not the only signs of pressure.

 

[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?

I always thought it was strange that reloaders thought that their loads were at safe and reasonable pressures as long as the brass is not damaged. If a proof load would give 75,000 PSI at the factory wihout blowing up or damaging the rifle they set the max operating pressure at a much lower pressure such as 62,000 psi for a margin of safety. You can probably load above 62,000 psi only because your in the margin of safety area.

 

[Webster]

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



I like this.

At work we had the math department design experiments so we could get the most value out of 3-4 variables. I don't see how QL can account for 10-20 variables all inter reacting and a few unknowns. QL says that if their velocity doesn't match the chro fudge one of the numbers to force them to match???? I go by the real data by looking in several reloading manuals and trust their max loads. I value my eyes, hearing and life. An exploding action is no different than a grenade going off 24" from your face.

 

[Flouncer]

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.

The Lee book does not list "loads" or tested anything, or shot it. Lee simply took available powder data from the powders shown and reduced by 10%. The Lee load of 45 is really about 50 grains. That's all I have. My Modern Reloading does not list H322 with 125g but for 130g and the load is 44g. For a 118g bullet, 48 or even 50g not so hot looking at it from my armchair !!

 

[Laurie]

At work we had the math department design experiments so we could get the most value out of 3-4 variables. I don't see how QL can account for 10-20 variables all inter reacting and a few unknowns. QL says that if their velocity doesn't match the chro fudge one of the numbers to force them to match????

QuickLOAD usually works remarkably well although there are caveats over a few default powder values. It allows many combinations to be tried for which there are no published data. For instance, look for published data for 308 Win using SP 'Palma' type brass and you simply won't find any. Look for loads like the OP's with a very short bearing surface 118gn BR type bullet and you probably won't find any and end up extrapolating from a table for the nearest approximate bullet which may have very different characteristics.

It is moreover an excellent way to save time, components and barrel wear in initial load development - all of the powder and bullet companies start with QL to put themselves into the likely correct powder choice and charge weight bracket with new loadings, bullets and / or powders - as they did with the much simpler and cruder Powley 'computer' in pre-PC times.

Certainly, to jump straight into a QL calculated loading expected to produce just below maximum allowed pressures whilst using the program's default values for case capacity etc is extremely unwise, not to say downright stupid, and the compiler warns against that sort of practice strenuously. Also, cross-checking published loads data (if available!) and even more crucially using a chronograph is very important. When trying something new I'll take a note of expected MVs that QL expects to achieve with the test charges, also that MV which the program expects to hit max allowed pressures with the combination with me to the range. Occasionally, I'll bring my highest charge test batch home unfired if actual MVs from lower charges suggest it is likely to produce dodgy pressure levels.

 

[corning]

This sounds so wrong...76,000 PSI in a .308 case...

 

[APGE]

This sounds so wrong...76,000 PSI in a .308 case...

Potentially 76000 psi, not measured. QL comes up with that, but the whole point of my post is that nothing else suggests pressure in that vicinity. @Laurie makes some very good points about the anomalies.

 

[David101]

Its pretty easy to work out your general level of pressure from the handbooks load data vs pressure and Muzzle velocity. From there you take into account how much extra powder you have added, what the MV is, what the COAL is and if they are jammed. From that you have a starting point and then take into account all the additional components that would add pressure.

The head size of the brass will also give you an indication. Will it still fit in a shell holder? I have loaded rounds that show no other signs of pressure other than the increased head size. This was using a custom action built like a tank. I would not do it in a Remington 700.

 

[spclark]

QL is a handy tool for dealing with unknowns during load development, but it's no substitute for actual chamber pressure data.

Forum posts about chronographs have been a popular topic; threads about ET's and their development and proliferation into some disciplines can get into some rather esoteric arguments. But little gets asked about how real data on chamber pressures can be gained? It's left up to the propellant companies to publish load data for their products, numbers that are generated with pricey equipment, by trained individuals who know how to achieve relevant data, but not in the actual chambers we're using day to day.

A forum member here, experienced in how QL can be used, who was willing to help me with initial load development for a 7mm wildcat using 308 brass in early 2016, greatly helped shorten the powder selection process. But as I was into 'unknown territory' with case volume exceeding that of the venerable 7-08 I felt it worth my while to gain more insights into what was actually going on in the chamber of the barrel I'd had chambered for this cartridge when working up loads.

And yes I was planning on using Lapua's small-primered Palma brass for this exercise.

I'd made 'guesstimates' before with new powder selection for another cartridge design, but that was done using data for that powder in cartridges having capacities on both sides of the one I was working with and using the same bullet weight. Still I returned home the afternoon I'd first tested that stuff with five rounds left unfired. The five at a charge weight a grain less showed pressure signs that kept me from even considering whether it was worth the risk to try the highest load. The lowest produced the least vertical dispersion at a velocity I'd expected to work with so that was enough.

I'd briefly mentioned earlier in this thread a system that can be used to get real data about chamber pressures. Priced about the same as current high-end chronographs and ET's, once you're used to the software (runs only on PC's) users can gain insights into other significant aspects of internal ballistics information besides chamber pressures being generated. Here's a link to where you can access the product's manual in PDF format; here's another to the home page for the product itself.

My motivation in posting all this is strictly in the direction of perhaps saving someone reading this thread from an unfortunate, preventable personal mishap. Reloading can be a safe, practical hobby as well as a means to achieving accuracy unobtainable with anything available over-the-counter.
But it must be acknowledged that there are practical limits. Systems like this one can help us learn what those limits are after everything else leaves us guessing.