Thread: Advice please

Yup scales probably part of the problem. I use check weights at the start of every loading session and that rules out one source of variation.

Originally Posted by grandpamac

Greetings @Hunterdave,
I think I may have an answer. AR2209 was sped up around 2,000 and the Hodgdon/ADI max of 53.5 grains of AR2209 with the 162grain has pressure in CUP which suggests it was for the older and slower powder. You seem unable to provide velocity for your load but if it is anything over 2,750 fps then your load is too hot. This may be from the powder or the Norma cases may have less capacity than the Winchester cases used by Hodgdon. In short if your velocity is over 2,750 fps then your loads are almost certainly too hot.


Regards Grandpamac.

Velocity is 2820 fps, when looking at book data wouldn’t that be for sammi spec OAL?

Originally Posted by Hunterdave

Velocity is 2820 fps, when looking at book data wouldn’t that be for sammi spec OAL?

That's probably with a 24" barrel though.

20" 284 owner here. I get 160's going 2715 with Re16 and it's a warm load. Re16 has always given more speed than 2209 for me so 2209 would be getting hot at that same velocity.

Having now ruled out case and powder variables I'd say load was originally right on max and is now over max due to possibly carbon build up or the throat has roughened up or any number of other reasons.
Give it a dam good clean for carbon especially in the first two inches of throat and if no change well you have to reduce your load or accept short brass life and increased risk.

You're deffinately too hot. I would choose a slower powder and check the theoretical pressure using Quickload /GRT. Or have one of us help you with that. You might be leaving a better and safer option untried.

I will check for carbon ring with bore scope today. With velocity being no higher than previous is it possible this could be a head space issue?

Originally Posted by chainsaw

I have a 2209 load in 20in 284 running 154 SST's & that's also 53.0gn with COL 3.100. Its not showing any pressure signs but probably getting up there.

You're showing ALL the pressure signs mano.

Some rough numbers from GRT:
Maximum pressure: 63,817psi

Your Load: : ~66,300psi
162gr ELD-M, 3.113", 2820fps, 20", 21°C

.Quickload calculates 20" barrel at 2701fps is 60.000psi @ 30°C with H4350 (earlier version of AR2209 is definitely slower) and that is without knowing the case capacity...could very well exceed the max of 63817psi with a smaller case capacity than what I have used.

Looks like @Pommy is bang on with velocity max 2715fps.

there are ejector rings on row of cases to left of tray......by the W on top two.

Originally Posted by Hunterdave

Velocity is 2820 fps, when looking at book data wouldn’t that be for sammi spec OAL?

Greetings @ Hunterdave,
The Hodgdon data loads have the 162 grain Hornady BTSP at 2.97 inches or 75.4mm which is longer than SAAMI max, Some years ago John Barsness came up with some rules including one on the relationship between case capacity and velocity using printed hand load data. He later validated them with his own chronographing. The rule is that possible velocity increases by one quarter of case capacity as a percentage. I have used the rule when sorting out appropriate loads fo my 6.5 and it works well. The additional case capacity for your LOA of 79.1mm over the Hornady load calculates to 2.2 grains or 3.6% bases on the Nosler case capacity adjusted for the longer Hornady LOA or 0.9% increase in velocity. This works out to 25 fps or 2,872 fps in a 24 inch barrel. With your 20 inch barrel this would drop to about 2,770 max velocity. I note that Nosler lists a max of 51.5 grains of H4350 (AR2209 in a different bottle) for the 160 grain Accubond. People often claim huge increases in velocity for seating the projectile out for added capacity but this is at the expense of higher pressures. In short your powder is hotter than that used in the Hodgdon Data, as verified by my own chronographing with my 6.5, and your load needs to be reduced. Please ask any questions you might have Forum or PM.
Regards Grandpamac.

also..previously only neck sized...now been FLR ...so if dies squeazed sidewalls in even a tiny bit...it will have reduced case capacity by a tiny bit.....when you standing on edge of cliff leaning outwards...a tiny bit can be worth a lot....there are ejector swipes on other cases further back in tray too.

Originally Posted by T.FOYE

You're showing ALL the pressure signs mano.

Nope, no pressure signs and safe in my rifle. Have since changed to slower powders for heavier pills RL17 and SPF

In regards to case sizing, was I right to size brass to bump shoulder back .002” allowing for a bolt fall with no resistance or should I have left longer so bolt closes with minimum pressure while not pushing shoulder back?

Originally Posted by Hunterdave

In regards to case sizing, was I right to size brass to bump shoulder back .002” allowing for a bolt fall with no resistance or should I have left longer so bolt closes with minimum pressure while not pushing shoulder back?

This is what I have gone to recently after neck sizing for years. 0.002 inches allows for free chamberingand removes the possibility of any tight ones. This assumes you are using a competition shell holder kit which I have found gives the most repeatable clearance.
GPM