Thread: Who says ADI max loads are soft

Here you go:
.300 RUM.
210gr SMK (#9420), 99.9gr AR2218
Spec: 64,842psi; 3072fps
3mm Over:61,457psi; 3027fps- to get this back up to 3072fps you would need to use 101.2gr AR2218
3mm Under:68,673psi; 3119fps
- Of course seating depth will have a greater impact on a chambering where the caliber to case capacity ratio is greater, because a change in seating depth changes the combustion chamber size by a larger percentage. I.E. your 9mm.

CUP or psi doesn't matter, there is still a limit right? Too much is still too much?

There is 0.30 grains of total H2O difference in SAAMI case capacity between .223 and 5.56

I realize ADI data is for a shorter projectile, hence why I gave data for the 69gr Sierra used by ADI, consequently even with that projectile and a charge of 2206H 0.5grain under stated ADI max, QL still suggests that would generate a chamber pressure in excess of 72,000psi

24gr AR2206H behind a 70gr Berger VLD could give around 62214psi in the 5.56 chambering.

QL should not be taken as gospel (and neither should what I say) but when predictions correlate with real world observations it adds weight to what was predicted. Like in this case. Perhaps @gimp might test for us a 69gr Sierra at max ADI loads and see if he gets another stuck case or some other high pressure sign? My guess is he wont be game enough to 26gr AR2206H (ADI max) behindthe Sierra when QL suggests it generates more than 77,000psi... Would you?

Originally Posted by Beavis

I'm shooting 68gr Hornady's in front of 26gr of 2206H, ADI brass. Goes mint. Plug that into QL?

83025psi.

Maybe.

What speed are you getting?

Originally Posted by Wildman

Here you go:
.300 RUM.
210gr SMK (#9420), 99.9gr AR2218
Spec: 64,842psi; 3072fps
3mm Over:61,457psi; 3027fps- to get this back up to 3072fps you would need to use 101.2gr AR2218
3mm Under:68,673psi; 3119fps

Very different in reality to my gun - 2217 and 208 Amax at around 94 IIRC (my data is at home) for that initial speed, and 98 when set out and finished. I may have gone 4mm or something, but its neither here or there

There is 0.30 grains of total H2O difference in SAAMI case capacity between .223 and 5.56

According to QL maybe, but in reality there is a big swing in case weight (= capacity)
The last batch of BLK brass we cut was very heavy
I can weigh and test a few when i get back as have a variety

24gr AR2206H behind a 70gr Berger VLD could give around 62214psi in the 5.56 chambering.

Perfect

QL should not be taken as gospel (and neither should what I say) but when predictions correlate with real world observations it adds weight to what was predicted. Like in this case.

I agree with the primer signs and QL results in this case - no questions asked
I generally agree with most things I see in QL, but it is nothing more than a equation end of the day

Perhaps @gimp might test for us a 69gr Sierra at max ADI loads and see if he gets another stuck case or some other high pressure sign? My guess is he wont be game enough to 26gr AR2206H (ADI max) behindthe Sierra when QL suggests it generates more than 77,000psi... Would you?

1 of my AR barrels with stick a case with ammo that the other bunch and bolt guns eat up all day. It just happens to be the most expensive one with the flashy name on it also.
Mate has same issues also, 2 barrels from same mfg and 1 will stick
I know for a fact that there is no issue with the ammo.. 10k + rounds have been fired of it and its a pretty generic load

69 Sierra 26gr 2206H 77000psi
68 Hornady 26gr 2206H 83000psi
If that is indeed true, then it goes further to push the point that you cant just swap out a proj and expect the same results.
Also that QL isnt always right (it is however scarily accurate with my 308) as 83k psi breaks lugs ARs quick smart.
That 68gr Hornady load is a SWEET load that is popular worldwide.. so 83k psi?? yeah nah...

I average it out at 2864fps from a 16" 1:7 twist barrel. I think from memory it goes to a high of 2870 odd fps. The primers are slightly cratered, but my carbine hums through them, no extraction issues. It fucks animals up real good.

Originally Posted by Beavis

I average it out at 2864fps from a 16" 1:7 twist barrel. I think from memory it goes to a high of 2870 odd fps. The primers are slightly cratered, but my carbine hums through them, no extraction issues. It fucks animals up real good.

Yep well QL suggests you should be getting about 3068fps so I am guessing you have a slow barrel or a sloppy chamber or something?

I thought that was pretty good for a 16"

Originally Posted by Spanners

Very different in reality to my gun - 2217 and 208 Amax at around 94 IIRC (my data is at home) for that initial speed, and 98 when set out and finished. I may have gone 4mm or something, but its neither here or there



According to QL maybe, but in reality there is a big swing in case weight (= capacity)
The last batch of BLK brass we cut was very heavy
I can weigh and test a few when i get back as have a variety




Perfect



I agree with the primer signs and QL results in this case - no questions asked
I generally agree with most things I see in QL, but it is nothing more than a equation end of the day



1 of my AR barrels with stick a case with ammo that the other bunch and bolt guns eat up all day. It just happens to be the most expensive one with the flashy name on it also.
Mate has same issues also, 2 barrels from same mfg and 1 will stick
I know for a fact that there is no issue with the ammo.. 10k + rounds have been fired of it and its a pretty generic load

69 Sierra 26gr 2206H 77000psi
68 Hornady 26gr 2206H 83000psi
If that is indeed true, then it goes further to push the point that you cant just swap out a proj and expect the same results.
Also that QL isnt always right (it is however scarily accurate with my 308) as 83k psi breaks lugs ARs quick smart.
That 68gr Hornady load is a SWEET load that is popular worldwide.. so 83k psi?? yeah nah...

The thing with QL is the rifle is not taken into account. It is simply a model based on case, powder and projectile specifics. The rifle has nothing to do with it. It is just a prediction. As I understand it though if you measure as many of those variables and measure what comes out the end (speed which accounts for rifle variables) then you can get an indication of the pressure required to reach said speeds... Like @Beavis's example. QL suggests he should only need 24.4gr 2206H to reach his 2864fps from a 16" barrel with all else being equal. This is at a predicted 65,000psi. But because, I am guessing, his rifle variables, he needs an extra grain and a half of powder to reach said speeds.

If you really wanted to get pedantic with case capacity, you can measure and change those variables in QL but I dont have the time or energy to do it. Your reloading practice should always air on the side of cation and allow for a worse case but starting low and working up. Again QL is only indicative but if you play with it enough you will figure out which variables are the one that have the greatest effect on speed and pressure. My observations are that seating depth, especially on magnums and anything over bore, plays a lesser role...

All I will say is that I would be bloody careful about picking and choosing the results you use and which you dont. I dont believe you can get money for nothing with gun powder, so if you are getting super speeds then it is likely due to there being enough pressure there to push the bullet that fast; and if QL suggests that that pressure is 10k or 15kpsi I will be bloody worried...

And the whole point I am arguing is exactly that, there are no free lunches.

Originally Posted by Beavis

I thought that was pretty good for a 16"

Apparently you should be able to get that from a 12.5" barrel for that amount of powder...

Maybe something to do with AR's?

Originally Posted by Wildman

Apparently you should be able to get that from a 12.5" barrel for that amount of powder...

Maybe something to do with AR's?

2 words, milspec chamber

I'm off tahr hunting I'll read all the rest of this later

Originally Posted by gimp

2 words, milspec chamber

I'm off tahr hunting I'll read all the rest of this later

Which means what? Sloppy?

Dont read it, its boring:-)

Originally Posted by Wildman

Which means what? Sloppy?

Dont read it, its boring:-)

Longer throat. Military loads are generally very hot in 5.56

Ripped from M4C

" With all other things being equal, the 5.56mm NATO chamber with its longer and shallower angled leade and longer amount of effective freebore will produce less chamber pressure than a .223 Remington chamber, when firing .223 Remington SAAMI Spec ammunition. Because of this, 5.56mm NATO amunition can be loaded to a pressure that would be considered excessive in a .223 Remington chamber, yet acceptable in a 5.56mm NATO chamber. (Pressures are measured using different methods between the two systems.)"

There ya go