6.5mm 140 AMAX Velocity

[The Gump]

Gun:
-R700
-24" Bartlein
-.260 Rem

Load:
-Winchester .243 brass necked up
-140 AMAX
-44.5gr H4350
-Federal 210
-2.875 O.A.L.

Conditions:
-61 deg. F
-1600 DA

Yesterday I shot this load at 705yr. When I put all the data into shooter and backed my velocity out I got 2760fps. Does this sound right?

My chrono is currently down because I shot it... on accident.

Thanks

Edit:
-I was getting 2800 with 142 SMK's and 43.5gr.
-I did start into a new keg of powder.
-Old lot: 80511114917
-New lot: 80307125011
-Assuming the orange sicker on the side of the keg is the lot #.

 

[Hondo64d]

Re: 6.5mm 140 AMAX Velocity

43gr H4350 in Win 7mm-08 Brass gives me 2783 from a 24" Brux.

John

 

[Brandon05_88]

Re: 6.5mm 140 AMAX Velocity

I ran a pressure/velocity test with 140 A-max 2 or 3 weekends ago with H4350. AIAE MKIII with .260 AINA barrel...Bartlein 1:8.2" twist 5R 26" long.

Load(s):
Lapua brass
CCI BR-2
H4350 41.5-44.5 grains
2.918" OAL (20 thou off lands)

41.5 gr - 2754 fps
42.0 - 2807
42.5 - 2830
43.0 - 2842
43.5 - 2879
44.0 - 2892
44.5 - 2917

Chrono was 16' from muzzle
73* F, 59% H, 1900' DA

Zero pressure signs, primers were all normal. No ejector marks on brass.

H4350 8lb keg lot number: 80405125011

I was shooting 142 SMKs at 2825 before I started messing with the A-max. That load was:
Lapua brass
CCI BR-2
43.4 gs H4350
2.895" OAL (50-ish thou off lands)
142 SMK

 

[Niles Coyote]

Re: 6.5mm 140 AMAX Velocity

I am getting 2824 for 10 shots with the 140 A-max at 44g of H4350 in Lapua brass from a 24" Obermeyer, FWIW, there seems to be a newer lot out there that is running a little slow. Velocity taken with the magnetospeed.

 

[jfseaman]

Re: 6.5mm 140 AMAX Velocity

'Custom' Weatherby Vanguard, I built it. All Vanguards are based on an action using a one-piece forged and machined, flat bottomed receiver and a machined steel bolt with dual opposed locking lugs. This modified Mauser action is built to Weatherby specifications by Howa in Tokyo, Japan. It's not a Howa 1500.

28" oal Pac-Nor 3L, 1/8 twist, target weight, 260 Rem
New Nosler 260 Brass
CCI 200 LR
Hornady A-Max 140
H4350
2.896 OAL (-.010 off lands)

starting load of 41.5grns got me an average of 2720 with MagnetoSpeed chron, this is an accuracy node with this rifle. Made 50 cartridges and ran many sub .5 MOA. One 200 yard 3 shot was .432", what is that .2ish MOA. 100 yard groups mirrored 200 yard groups. Using Strelok I plugged in the numbers and rang the 4" swinger at 400 yards on the first shot and continued until time to let the barrel cool. Wind change took one shot off then was on again. Return to zero at 100 yards was sub .5 again.

Worked up to 42.3 was only up to 2805, 41.7 was same fps as 41.5 but lost accuracy. 41.9 opened up a little more still and no velocity improvement, 42.1 jumped 50fps but did not 'work'.

I'm looking for the mid 2800s node.

Point of the above. YES YOURS SOUNDS RIGHT and I wanted to tell someone who may care as I am very pleased. 260 Rem is a very nice cartridge.

 

[JWV]

Re: 6.5mm 140 AMAX Velocity

42.0 H4350
140 Amax
2.835 OAL
28 inch barrel
2830 fps

 

[Prebanpaul]

Re: 6.5mm 140 AMAX Velocity

tagged as I just got a magneto speed and just got a 260.

 

[Greg Langelius *]

Re: 6.5mm 140 AMAX Velocity

28" 1:8" L-W barrel, Win Brass, CCI BR-2, 140 A-Max @2.895" OAL (.010" off lands), 43.8gr H-4350, 2850(-ish)fps. Holds the 10 ring (average 30-35 of 40 shots) at 1000yd under match conditions. Not max, but getting near. Honestly, I'd be just as happy with a lower node.

 

[The Gump]

Re: 6.5mm 140 AMAX Velocity

It's looking like the lot I have is on the slow side. Honestly this is the first time I finished a keg, started a new one, and was required to pay attention to the effect of the change. In the past I didn't pay much attention to anything but signs of pressure because I was only shooting short distances. It's interesting. Should I expect this with any given powder in the unforeseen future?

Thanks for the insight.