284 Win Maximum pressure to maintain primer pocket size

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pgcpty
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284 Win Maximum pressure to maintain primer pocket size

#1 Postby pgcpty » Tue Jan 12, 2016 9:21 am

Anybody out there that knows from experience the pressure limit to not exceed to preserve primer pocket size in 284 Win (Lapua 6.5 x 284 resized brass)

Am working up 284 WIN loads with aid of QuickLoad (calibrated) and a Magnetspeed Chronograph so can predict pressure with a reasonable degree of certainty.

All help appreciated

Thanks

Peter
Good judgement comes from experience, experience comes from bad judgement!

pjifl
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Re: 284 Win Maximum pressure to maintain primer pocket size

#2 Postby pjifl » Tue Jan 12, 2016 9:53 am

I find that with 180 grain VLDs being driven by 2209 a velocity from a 30 inch barrel of 2850 f/s would be starting to degrade cases.
Certainly up around the 2900 f/s will kill my cases in a few shots.

I run just over 2800 f/s. Have found a nice node at about 2810 - 2820 and a 284 at that load (from Lapua 284/6.5 cases) is my workhorse rifle.

If I want higher performance that is what the 7 SAUM is for.

I suspect you can be kinder to the cases with other powders but 2209 does give excellent accuracy and I use it for many other rifles and you can buy it in 4 Kg lots so will stick with it.

Peter Smith

pgcpty
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Re: 284 Win Maximum pressure to maintain primer pocket size

#3 Postby pgcpty » Tue Jan 12, 2016 10:53 am

Thanks Peter,

Putting your info into QL gives me an estimated pressure of 56,823 psi based on assuming a COL of 3.226" so I guess 56,800 is a safe limit irrespective of the pill weight

Any comments?
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pjifl
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Re: 284 Win Maximum pressure to maintain primer pocket size

#4 Postby pjifl » Tue Jan 12, 2016 11:24 am

No idea of actual pressures but performance indicates it is safe in my equipment and does not bash cases.
Probably the best generally available indication of pressures is to measure primer pocket. Examining the primer flattening can be misleading.

Somewhere I read of a pressure max spec on 284 WIN of 64000 psi.

How good is QuickLoad ? It cannot know about tight and loose barrels ?

Start a new barrel lower for a lot of reasons and work up.....

I think Velocity is one of the best parameters to work on when starting a barrel or load or cases. We can measure it easily and fairly accurately.

Peter Smith.

pgcpty
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Re: 284 Win Maximum pressure to maintain primer pocket size

#5 Postby pgcpty » Tue Jan 12, 2016 12:16 pm

Peter

Somewhere I read of a pressure max spec on 284 WIN of 64000 psi. Agree

How good is QuickLoad ? It cannot know about tight and loose barrels ? Very good, QL's parameters can be adjusted to reflect a tight barrel

Start a new barrel lower for a lot of reasons and work up..... Agree, that's how I got parameters for QL from test results off my Magneto speed

I think Velocity is one of the best parameters to work on when starting a barrel or load or cases. We can measure it easily and fairly accurately.
Agree, putting measured average MV back into QL for a measure barrel length, case volume and COL enables QL to be calibrated to track results by tweeking start pressure/burn rate if necessary


Had QL for a few years now and find it invaluable, but I'm a fiddler and Engineer by profession. Its not for everybody, just those who must tinker :D
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ecomeat
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Re: 284 Win Maximum pressure to maintain primer pocket size

#6 Postby ecomeat » Tue Jan 12, 2016 7:02 pm

I use QL, and load for 4 barrels (3 x Bartlein 5R's and 1 x Maddco) in straight 284 Win based on a BAT Model M action. I use mainly Lapua 6.5 x 284 brass, although have also used 200 Norma cases. Mine are all chambered with a 0.313" neck, so I am neck turning to 0.013" to give me a loaded round of 0.310" so I have clearance of 0.003"
A couple of things jump out at me from your data.
MY QLV3.8 has a PMax of 63817psi
Your shot start pressure is 3636....standard for a Jump.
Case Length 2.170 ?? Mine are trimmed to 2.152" and the longest that I have ever measured were a couple of dodgy Norma cases that were just over 2.163/4. With a case length of 2.152" I have a H2o capacity of 66.66 gr, yet your cases are 18 "thou" longer and hold 0.66 gr less.........where logically they should hold more. How many cases did you weigh and average , to get 66.0 ?

Also your load of 52.5 gr of AR2209 in a 30" barrel is pretty hot ! After rethroating one of my barrels by 0.040" I had to take my 2209 load of 50.8 gr up to 51.6 or so to hold the same 2820-2830 fps. What velocity are you actually registering with 52.5 gr ? Your QL page says 2821 fps, but that doesnt seem quite right. From my limited experience (3.5 yrs with a 284) that is a fairly hot load and is going to be very hard on primer pockets.
Logically, if you are "Jumping" (from your start presure you have to be) and are only getting 2821 fps from 52.5 gr 2209 you must have an extremely long jump ! :shock: :shock: What is your own measurement of "touch" ? And what method do you use to arrive at that "touch" measurement ? How far are you jumping the 180 gr VLDs, do you reckon ?
Temperature : Have you adjusted the temperature up from the "default" 70 deg F to reflect your current summer temps ?
I am now running two (2) barrels at 2860-2870 , but the cases I am using were loaded with a light load of 2208 for fireforming , that only ran at about 2720 fps, and then had a further 4-6 loads of 50.6 to 50.8 gr of 2209 to get 2825 approx fps......and then re-throated and load now up to 51.8 (2860-2870 fps) for 2-3 firings and zero pressure signs.
However, I would think your 52.5 gr load should get you 2950 + fps easily.....and some very dead primer pockets.Unless you are jumping about 0.200" to be able to lose all that pressure you should have with a load that hot.
Have you actually shot 52.5 gr 2209 with 180gr VLDs over a chronograph yet ?
Tony Berry
Extreme accuracy and precision shooting at long range can be a very addictive pastime.

Robert Chombart
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Re: 284 Win Maximum pressure to maintain primer pocket size

#7 Postby Robert Chombart » Tue Jan 12, 2016 7:15 pm

pgcpty wrote:Anybody out there that knows from experience the pressure limit to not exceed to preserve primer pocket size in 284 Win (Lapua 6.5 x 284 resized brass)

Am working up 284 WIN loads with aid of QuickLoad (calibrated) and a Magnetspeed Chronograph so can predict pressure with a reasonable degree of certainty.

All help appreciated

Thanks

Peter


Max pressures CIP or SAAMI are 4400bar or 63000psi.
Better to always stay Under as signs of pressure can appear before max admissible pressure is reached.
But those figures are maximal and does not take into account case life.
Pressure is not factor only of bullet type/weight, and powder type/weight for a given caliber, but other factors make it vary from one rifle to an other:
-Throat diameter and angle.
-Barrel length ,grooves/lands diameter and for some extend twist rate.
-Position of the bullet to the throat.
-Case capacity (vary from one brand to another)
-Chamber/case neck dimensions (if no expansion made possible on firing, pressure rise can be exponential).
Atmospheric conditions.
List not exhaustive…
Those parameters are not cared for in calculators.
R.G.C
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R.G.C.

macguru
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Re: 284 Win Maximum pressure to maintain primer pocket size

#8 Postby macguru » Tue Jan 12, 2016 7:21 pm

Just get a saum and save yourself the heartache !
id quod est

KHGS
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Re: 284 Win Maximum pressure to maintain primer pocket size

#9 Postby KHGS » Tue Jan 12, 2016 7:34 pm

macguru wrote:Just get a saum and save yourself the heartache !

Or, just pay attention to what Peter has said, it is spot on advice & should be heeded. Tools such as QL are useful but their "advice" should not be taken as gospel across the board.
Keith H.

Old Trev-39
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Re: 284 Win Maximum pressure to maintain primer pocket size

#10 Postby Old Trev-39 » Tue Jan 12, 2016 8:25 pm

I have shot straight .284 win. on and off for around 10 years in F/Class and 1000yd B/R. I have found that my best results with 180 Sierras as I only use Sierras is51.7/2209 with .040 jump gives me2830/ 2835 from the various barrels I have used. Tried 52.2 one day and only shot 3 shots as bolt lift got heavy in my Barnard action. Have had good results with this combination.
On saying that my best long term results and the load I use at the big N/D Southern Cross 1000yd. B/R competition is 52.5/2209 behind the 175gr Sierras wit the same .040 jump giving2869 fps. I will continue to use this load until I come up with something that will shoot better. I have done some measuring of Berger projs. and find to many varyinces to be able to put together a number of uniform projs. to shoot matches.
Cheers,
Trevor.
P.S. case life is. quite good with these loads. Still using the same 50cases first loaded 13-1-13 and 12 reloads.

willow
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Re: 284 Win Maximum pressure to maintain primer pocket size

#11 Postby willow » Tue Jan 12, 2016 9:21 pm

I'm certainly not getting near these velocities, but for what it's worth I am loading 54.2gr of 2213sc. Barrel is a 30" Brux, velocity is 2700fps. After 5 firings (Lapua brass) primer pockets are still just about as tight as the first firing. Haven't bothered to push for pressure as the load seemed accurate enough so I've stuck with it.

pjifl
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Re: 284 Win Maximum pressure to maintain primer pocket size

#12 Postby pjifl » Tue Jan 12, 2016 9:34 pm

I never mentioned my powder load for a reason.

With one batch of 2209 I needed 51.5 grains, but with the present batch I am using 50.5 grains and have just pre-tested a new container of 2209 but have not been seriously using it yet. All indications are that I may need slightly less powder again. That is to achieve 2820 f/s.

I am convinced the first mentioned lot was not normal. All of this is the result of scratching together enough powder after a real shortage of 2209 about 6 - 12 months ago in NQ and having to rely on 'dregs' and now at last finishing the different batches off.

But this weaker powder shot extremely well in Brisbane once I calibrated the load to the velocity I wanted.

Velocity is so easy to measure these days, and it puts you back in the known accuracy nodes almost immediately.

One of the best things about using Velocity is that you can still measure it when the wind is howling and the sighting is sh*t so you cannot other wise test a rifle for accuracy.

Of course, if you can by all means do so. But I and a few others have found certain velocities bands seem a very good starting point and often cannot be improved upon.

Peter Smith.

pgcpty
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Re: 284 Win Maximum pressure to maintain primer pocket size

#13 Postby pgcpty » Wed Jan 13, 2016 5:22 am

Re Tony Berry's input.

Thanks Tony,

I've only had one outing with my 284W and have included 1st shoot results.

As my question related to maximum breach pressure to preserve primer pockets I put your figures given into QL and flexed the 2209 powder load to reach 2925 MV with a resulting QL pressure prediction of 57,642 for 80 deg F (27 C).

If your happy with my interpretation than the Pressure Ceiling to not exceed is say 57,500 psi?

I only have 100 cases and don't wont to buy any more till the Bertram brass is available

Thanks to All

Peter
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ecomeat
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Re: 284 Win Maximum pressure to maintain primer pocket size

#14 Postby ecomeat » Wed Jan 13, 2016 7:49 am

Peter, I will have to take the fact that I only just worked out who pgcpty is, as proof positive that I am well on the way to senility :D Bloody engineers !
Hopefully you are happy with your initial testing. That 51.4 looks pretty good, at 150 yards.
The only thing I can see "out of whack" , is that it seems you have tweaked QL to 2825 fps and not to 2925 fps ?
Those max pressure figures are pretty close to where I believe I am running, 57,000 plus PSI, but ........I am using brass that has been tempered, or "broken in" with lower charges first, and in a barrel that is fully seasoned.. Based solely on the powder charge of 2209, (52.0 gr, and completely ignoring velocity) I would think you would have to be damaging primer pockets of new brass if you use that load in brand new, previously unfired cases.
BARREL : You said that the groups posted were your first outing. So how many shots through the barrel when you finished at Silverdale that day ? Are those the first 30 or so shots through the barrel ? If they are you had better send it straight up to me for safe keeping and buy yourself another decent barrel ! Or had it previously had maybe up to 50 shots or more through it to "break it in", set scope up, foul barrel etc etc ?
I did win a Prize Meeting at Warwick last year with a new Bartlein 5R that only had about 60 rounds through it when the day started, and carefully cleaning between ranges, but I had always believed that a normal plan would see a barrel get over/through the inevitable "speed hump" at 150-250 rounds where they commonly speed up 50-100 fps. before settling on a load.
If that testing you posted actually ended with less than 50 rounds through a brand new barrel, I can easily understand the overwhelming desire to be competing with it immediately, coz you should seriously manage to kick some arse, right from day one, but I will go out on a limb and predict a short barrel life, and new cases required after 3-5 firings.......or less :D :shock: :D. if you do run it with that much AR2209 right from scratch.
Extreme accuracy and precision shooting at long range can be a very addictive pastime.

williada
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Re: 284 Win Maximum pressure to maintain primer pocket size

#15 Postby williada » Wed Jan 13, 2016 10:17 am

Peter, unless you are running a pressure trace on the barrel it’s hard to know with certainty what is really happening due to variables as learned gentlemen have expressed. I use a digital calliper and take a measurement in the extraction groove on a case and don't like this to enlarge more than .001" while they are new as a rough guide. Like Peter S, I am wary of just examining the primer appearance as these can hide other mechanical issues with the firing pin as just one example.

What Tony has done is condition his cases so they gradually harden to cope with hotter loads. This is very important to reduce some variables as is getting a barrel over the hump of conditioning for fine load development for its longer term use. It is also important to work up loads to find the maximum load for further load development in planning the first ladder test to find a suitable node to further fine tune; so I don't mind sacrificing a few "conditioned cases" (on third firing) to find that. I try to use a few throat break-in cases over a few times which gives me a few cases that are expendable in determining the max load for ladder testing over the chronograph.

As for target results, finding the right node is the tricky bit. Beware that all tight groups up short are actually best for that distance and how much they open up at further distance may require some minor adjustment of your barrel launch angle. Generally speaking groups hold their shape but may enlarge at distance not specific to tune but maybe tight enough to stay in. Your experience with tuners is on the right track Peter. The gear looks promising.

Groups don’t hold their shape as well on ranges dominated by turbulent air. This requires a higher velocity node to punch through the turbulence which may not be as tight as a lower velocity node but give you a better outcome in terms of score. You are at a disadvantage competitively if your node selection is in the wrong place and you are effectively just going bang with little return for effort unless you can manage larger groups with a higher velocity node. Turbulent air throws logical pattern formation out the window. So for championships, losing the primer pockets is small beer when conditions demand higher velocity so long it is a safe load.

Denser air is not the same as turbulent air, and a chronograph will soon reveal the speed you require to maintain your preferred accuracy node or you can adjust your launch angle with your variable tuner.


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