.5 gr below max for a bullet 1gr lighter with the same profile!
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.5 gr below max for a bullet 1gr lighter with the same profile!
Attachment 18521
Because a computer prediction is always the best indicator of pressure right:D
Quote:
Originally Posted by veitnamcam
Not pictured: removing case from the chamber with a cleaning rod. Chronograph speed 14fps off from QL prediction.
http://i58.photobucket.com/albums/g2...psvdhxxy1p.jpg
Nicely trimmed finger nails (although the whitlows could do with some attention).
Does that really say 12.5 barrel?
At least the new data layout on the ADI site has the projectiles listed.
Some calibres are fine others are way low ie 7mmRem mag, others can be a little hot.
I guess it comes down to chamber/brass dimensions & powder lot.
Ok looks warm:D
hence importance of working up and recognising pressure signs .
Some adi loads are soft tho.
Of course.Quote:
Originally Posted by Tahr
I got my data from an old ADI book, although the max load listed on the ADI site (not in the book) is still likely too hot.Quote:
Originally Posted by Kiwi Greg
Halfway between start and max load... Max load works out about 79,000 psiQuote:
Originally Posted by veitnamcam
I thought we established a couple of years ago that 80k psi is fine. You just need some hard lapua brass and all will be good.
And pressure gear wasn't reliable. .. . .
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I thought it was established that we can't measure chamber pressure accurately and etc etc, don't recall any conclusionQuote:
Originally Posted by L.R
Regardless I'm not shooting Lapua brass through an AR to be lost in the grass, the system has weaker extraction than a bolt gun, higher pressures aren't great for the longevity of the gun, and SAAMI max for 5.56x45 is 62,300psi or so, and book loads are vaguely meaningless due to variances in pretty much everything involved
So in short, I have no point here but I'm backing this off half a grain and re-testing
Adi 2225 in 300rum max load 100.5 behind a 180 grainer seems very warm looking at a couple of cases I acquired... they will be getting pulled
It's likely the internal volume of the brass coming into play. My friend has done a lot of load development with RG, it gets warm faster than FNB and I can't remember what else. The primer pockets on RG are cunty.
Quote:
Originally Posted by gimp
Yea I was only taking the piss. You are right it is pointless to shoot lapua brass in an AR and even more pointless to drive it to the point of troublesome extraction. If you wanted more speed you wouldn't start by cutting the barrel to 12.5".
It's the first load I tried, I wouldn't quite describe it as driving it to that point so much as inadvertently starting there
ADI max for a .260 using 140's and 2217 is 50.5 getting 2700ish in a 24" barrel.
I just went 54.5 compressed in my .260Ai and got 2850 in a 24" barrel. No pressure signs. I can't get much more in so had flag any idea of using it as I get way better fizz out of RL-17 for 7 gr less.
That was using fed mag primers and newly formed Lapua brass.
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Ive found the current adi data for 223 to be pretty much bang on
Nb max for 70gr in current data is 25gr. I found velocity etc for 69gr with 2206h to correlate perfectly (in my rifle) my other rifles in lother calibres always need extra to get close to the stated velocitys
Ive used 2209 and backed of .5 from pressure to get exact same speed same primers and brassQuote:
Originally Posted by R93
Yeah I was having a play because of advice given on a standard .260 that reached good speeds with 2217.
No where near it in my AI so will stick with RL-17 as it works.
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It's got fuck all to do with the ADI data, it's the fact you are fitting a VLD into a AR mag
seated to a normal length ie out a heap, and the pressure will plummet
I think his point is he plugged mid-range ADI data into Quickload and found that Quickload suggests the pressure is through the roof. His real world observations seem to back this up. This is completely against the commonly held belief that ADI data is anemic and well below SAMMI recommendations.
And my point is he has what would be considered an abnormal seating depth for that projectile in a 223 and thus why the pressure is high and predicted high.
His overall cartridge length is 0.03" longer than SAAMI specs for 223 and 5.56 Nato so I don't see how that could be a factor. Unless he has a short throat, but you cant account for that in Quickload.
It's loaded longer than the COL in the ADI data. I think. Going shooting now, will look later. This isn't a serious criticism of ADI or whatever
It is a hilariously compressed load. My only point would be that book data can be fairly meaningless
You're almost comparing apples and bananas and saying they are the same because they hang from trees :D
From what I have here at this time:
The Berger 70 gr VLD is 0.976" long.
The Sierra 69 gr SMK is 0.898".
(I dont have the HPBT Sierra, but from memory it is shorter again)
Given the same OAL, you're looking at an effective seating depth change back into the case of about 0.078" or close to 2mm
If the HPBT is shorter, you have increased that further again.
Seat the VLD out 2mm.. QL will tell you what you want (and expect) to see, and when fired (single load or bolt gun) the case will too.
Same same but different :pacman::thumbsup::ORLY:
Quote:
Originally Posted by Spanners
Still over 72,000psi... 10,000 more than spec max.
It is also worth noting that your 69gr SMK at spec OAL and 25.5gr 2206H comes out over pressure (~72,000psi)
Interestingly I just checked out the online ADI data and for 2206H they suggest a max of 26gr for the 69gr (Sierra HPBT spefcically), and only 25gr for a 70gr Speer SP.
I just don't think OAL has much effect on pressure unless it is extreme or touching the lands.
Also, QL was pretty good at predicting the speed (only 14fps difference) and that the charge gimp was testing would be over pressure....
Quote:
Originally Posted by Wildman
Take a factory Rem with 6+mm to the lands so they are out of the equation and go 3mm either side of SAAMI spec and tell me what you see - my RUM was about 4gr (from memory) MORE powder to get speed back after seating out
Ive found that depth makes a difference - from Pistol cals through to my big guns. I'm not concerned about where the rifling is as long is its far enough away. My 1st and only attempt at it resulted in a action full of powder and I lost interest in chasing them and in my guns, doesnt matter
2mm in a 9mm case can increase pressures to blow up levels
ADIs data is measured in CUP.. QL in psi...
ADIs data is in 223 Winchester cases, not 5.56 Mil cases...
ADIs data is for a proj that takes up 2mm less case space...
ADIs data is for a proj with a softer jacket
Fruit salad :D
A 2 min search online suggests all those shooting ARs using 2206H (which is 4895) with 70gr VLD are seeing max loads of around the 24gr mark
Whats QL say to that?
I'm shooting 68gr Hornady's in front of 26gr of 2206H, ADI brass. Goes mint. Plug that into QL?
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?
83025psi.Quote:
Originally Posted by Beavis
Maybe.
What speed are you getting?
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 thereQuote:
Originally Posted by Wildman
According to QL maybe, but in reality there is a big swing in case weight (= capacity)Quote:
There is 0.30 grains of total H2O difference in SAAMI case capacity between .223 and 5.56
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
PerfectQuote:
24gr AR2206H behind a 70gr Berger VLD could give around 62214psi in the 5.56 chambering.
I agree with the primer signs and QL results in this case - no questions askedQuote:
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 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.Quote:
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?
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.
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?Quote:
Originally Posted by Beavis
I thought that was pretty good for a 16"
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.Quote:
Originally Posted by Spanners
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.
Apparently you should be able to get that from a 12.5" barrel for that amount of powder...Quote:
Originally Posted by Beavis
Maybe something to do with AR's?
2 words, milspec chamberQuote:
Originally Posted by Wildman
I'm off tahr hunting I'll read all the rest of this later
Which means what? Sloppy?Quote:
Originally Posted by gimp
Dont read it, its boring:-)
