208gr A-max 308. win 2900fps

[Dimepuncher]

hello im new to this fourm, today i just got done testing my new 308 win load,
new lapua cases
208grA-Max
cci 200 primers
48Gr RL-17
OAL 2.985
2900fps at 30 Degrees temp.
i doint think many of you will believe me i was skeptical at first to but it wasn't a fluke my chrony read from 2919 to 2930 over the course of ten shots and this is from a factory savage M10le 26" barrel with great accuracy 4shots under a half inch and two called flyers bring the group to just over 3/4 ;D

 

[whiskey08]

holy smokes... thats a game changer. what do the primers, and other pressure signs look like.

Does the bullet trajectory confirm your chrono, I know my chrono is on crack most of the time. I dont use it anymore because its so inaccurate?

Alliant powder lists the max for 180 bullets at 48.7 gr and that is around 2600 fps

 

[Dimepuncher]

i only had a chance to shoot it at 100yrds today no no input from trajectory but it had a slightly sticky bolt and the primers look fine im beginning to wonder if my chrony is on crack to but its brand new with a fresh battery in it

 

[40X Guy]

I am under the assumption that RL-17 is gonna get you velocity, but that is rocking with a .308, I would think you would be lucky to get around 2500FPS on a good day. Bruce Artus's .308 AI only achieved MV's of 2400 fps with a 220 Sierra MK, and his gun is full blown custom with 28 inch Boots barrel and he's shooting over a mile out west in Colorado. So you may want to recheck your chrony. My .300 Ultra Mag is struggling to stay over 3100 fps with a 208 and I have an Oehler 35P Chrony. All while burning 94 grains of powder.

Frank

 

[Dimepuncher]

yeah i understand i don't relay believe it i think i will have to buy some factory ammo and see if i can get a velocity comparison / with a 45 gr load i read 2800 47 gr it read 2870 and 48gr 2900

 

[Dimepuncher]

i just found some 180gr remingtons rated for 2600 fps i will try them next weekend

 

[40X Guy]

That sounds about right with a 180 in .308, ~2600fps. Gotta keep the boiler room space big to match those big 30 cal bullets to get em thumping out of there.

Frank

 

[Longshooter70]

I've been running 49.1 gr RL 17, 208 AMAX, Win cases, CCI 200 primers in a Rem 700P 26". Oal was 3.010, 2.266 to ogive. My velocity was 2630 on a 60 deg day. That was as hard as I cared to push them. That velocity your stating is not the norm from what I've seen. I've done a lot of research on this and talked to a lot of people. I would check my drops at longer ranges and compare them to what my chrono says just to be on the safe side... Good luck..

 

[dennisinaz]

I think your Chrono is bad. Those velocities are just too far beyond expected. A fast barrel would be 75 fps better than normal!

I would think 2500 fps would be good! You need to shoot a 22 LR or similar over it to see what is going on.

 

[Laurie]

Sorry to rain on this particular parade, but I'm afraid there's simply not a chance, especially from a 26" barrel, and that in a factory rifle with presumably something close to a SAAMI specification throat too (ie the 208gn A-Max seated fairly deep in the case reducing combustion chamber volume and increasing pressures for any given charge weight)!

That bullet weight and MV equate to 3,885 ft/lb ME and NO .308W load in any barrel is EVER going to produce that figure. When I say won't ever produce that figure, I don't mean produce it safely, I mean at all, as it defies the laws of internal ballistics. You'd be on your way to the nearest hospital emergency unit long before you'd get up there!

To put 3,885 ft/lbs into context, the equivalent MV from a 155gn bullet is 3,359 fps and for a 175gn bullet is 3,162 fps to produce that amount of energy. These are values that you'd have difficulty in achieving with short magnums, or even the .300 Win Mag from 26" of barrel. Running the 208gn A-Max in .300WSM through an optimally throated barrel to give a COAL of 3.00" instead of 2.80" needs 64.0gn of Re17 to achieve 2,900 fps from 26" according to QuickLOAD. Unfortunately, even with the WSM's capacity, QuickLOAD estimates a peak chamber pressure of 68,584 psi, some 4,000 psi above the allowed maximum. You would probably just achieve it safely with a suitably throated WSM and 30" barrel.

I'd have the chronograph checked!

 

[Dimepuncher]

whoa easy now i already said i think my chrony is off im hoping to figure out how much its off by this weekend does any one know how accurate Remington's published velocity's are

 

[tdking]

Dimepuncher,
You can not shoot most factory loads and expect the velocity to match the published data. Too many variables in each rifle affect the velocity.

I would try shooting at longer ranges and determine the drop then back calculate the velocity that would give that drop using the published BC.

Another method is to compare your chrono readings with another chrono that is known to give accurate readings.

Keep us posted on what you find (good or bad).

TDK

 

[Dimepuncher]

well i figured it out ;D i was to close to the chrony i moved it out to 20 ft from 10ft and the velocity changed to 2650 with 48 gr of rl-17 and factory HSM 300 win ammo with 210 bergers was at 2870 and my 22lr was clocking at 1100 now for the best part i loaded some 240gr sierra matchkings in my 308 2450fps with 46 gr of rl-17 ;D

 

[Laurie]

That's still a nice healthy MV for the bullet weight. How did the groups look on your later tests? I've tried Re17 with lighter (185) bullets in .308W and while the velocities were good, groups were nothing to write home about. There have been several hints elsewhere on the forum that the powder suits bullet weights over 200gn though.

PS on the 240 SMKs watch out for barrel coppering. Bryan Litz describes this as a design with a too long bearing surface length making it prone to shed jacket metal in the barrel. Berger Bullets is presently working on a new generation of heavy modern design 0.308s and we can hope it pays off in due course. Have a look at:

http://www.appliedballisticsllc.com/index_files/30cal_fullVersion.pdf

for an article Bryan wrote some time back in his before-Berger days. He's not overly flattering about the 240 SMK.

 

[Dimepuncher]

i will keep an eye on the barrel thanks for that input im going to be doing some accuracy testing this weekend with the amax and the sierra's that last group i shot with the amaxs i had 4 shots overlapping under .5moa and the 5th and 6th my falt on those flyers opened the group up to just under an inch

 

[wapiti25]

I think the chrony needs checking. Try some match 22 lr ammo with an advertised vel. as a check. I have a friend that sent his Chrony in for repair and they said it was 8 percent fast. It would be great if that is a true velocity but you are talking 300 mag velocity. I had a 308 that would do 2700 with a 190 hornady and I thought it was fast.

 

[TC]

I tried the 208 in a 1:12 308 with 42gr Varget...blew the primers clean out and accuracy was pretty poor. Run any of the stability programmes and even if you could push this out to 3,000 it is still theoretically unstable in a 1:12. I didn't chrono but i worked up from the 39gr and 42gr was just too much.

 

[scout1]

These are values that you'd have difficulty in achieving with short magnums, or even the .300 Win Mag from 26" of barrel. Running the 208gn A-Max in .300WSM through an optimally throated barrel to give a COAL of 3.00" instead of 2.80" needs 64.0gn of Re17 to achieve 2,900 fps from 26" according to QuickLOAD. Unfortunately, even with the WSM's capacity, QuickLOAD estimates a peak chamber pressure of 68,584 psi, some 4,000 psi above the allowed maximum. You would probably just achieve it safely with a suitably throated WSM and 30" barrel.

I'd have the chronograph checked!

Since this seems to have died out I'll take a turn as it has two of the components I want to know more about, 208 A-Max and RL-17

I plan on running the 208 in a WSM with a 12 twist 28" Kreiger. Right now N-560 looks good on Q.L. with pressures and speed. My H2O capacity is 81.5 grns loaded to 2.930 with a .020 jump with 69 grns of N-560. 2950 fps +/- and it shows well under P-max. I am aware that this is a predictive program but it been pretty dam good to me with this powder and lighter bullets (Berger 175 vld).

Has anyone here tested the 208 in a WSM with RL-17

Would love to hear about any testing