Thread: AR2209 Lot Variations in the 6.5 x 55.

Greetings All,
A few months back I was developing some new loads for my 6.5 T3 and found some significant differences in burning speed between the current production and an earlier lot of AR2209. Sorting through some old loads some were found that contained AR2209 from an even earlier lot. It seemed a good opportunity to chronograph the three lots of powder with other variances eliminated as far as possible. I found the results interesting hence this post.

The three lots of powder were purchased in 1,993, called original, about 2,000, called old and 2,019, called new. Two different projectiles were tested, 120 grain Sierra flat base and 129 grain Hornady SST. The 120 grain projectiles were loaded in once fired Norma cases with Winchester W120 primers. These cases came from loads assembled in 1997 which were broken down to provide the powder. The cases, originally full length sized, were neck sized to restore neck tension. The 129 grain projectiles were loaded in new Lapua cases with Federal 210 primers. The shooting was done yesterday in cool overcast but breezy conditions at 60 metres. Mid chronograph screen was 3.0 metres from the bench. Loads for the 129 grain old and new lot powder were fired previously.

Velocities recorded are as follows:
120 grain projectiles 46 grains AR2209. Original lot 2,806 fps. Old Lot 2,798 fps. New lot 2,870 fps.
129 grain projectiles 45.5 grains AR2209. Original lot 2,763 fps. Old lot 2,720 fps. New lot 2805 fps.

The powder loads were max form the Hodgdon on line data which is limited to 46,000 CUP. The old lot of powder produced velocities close to Hodgdons. The new powder velocities are closer to the Nosler on line data. Nosler seems to have reduced the loads for their 129-130 grain data perhaps due to some harder projectiles in that range.

Results: There is a little less than 100 fps difference between the fastest and slowest lots of powder, equivalent to adding roughly 1.5 grains of powder in this case. A powder load adjustment would be needed with close to max loads. All loads other than the 120 grain new powder loads went into a 17 mm group with individual loads moving around in this group, a little less than 1 MoA. The errant loads went about 5 mm high.

Conclusions: Yes we do need to make adjustments when a new lot of powder is started but we shouldn't need to work up from start loads if you have a chronograph. Checking a start load of each lot of powder over the chronograph should tell you if the lots are similar or not. Adjustments can then be made. Velocity is the best measure of pressure we have as hand loaders.
Regards Grandpamac.

I'd say all true except not all chronys are made equal.

Just mix the powder all together and then it's all the same batch.
It works.

I'd expect much of the variation is due to age as much as it is lot variation. A lot of time to be exposed to different environments, humidity levels and temperatures

Greetings Gibo, Tribrit and Nick-D,
Thanks for your posts.
Quite right Gibo all chronographs are not created equal. Mine is an Oehler 35 P that I bought in the early 1990's. I remember that it cost $850.00 from Reloaders, about the cost of a new rifle and scope at the time. I run a four foot screen spacing and although I don't use the printer any more still use the three screens to validate the readings via the proof channel.
Yes Tribrit I could blend the lots for a single batch which after all is what the manufacturers do to reduce lot variances or did anyway. There are usually at least two rifles in the safe using each type of powder that is in stock. I only use three powders, AR2206H, AR2209 and AR2213SC in most of my rifles so one rifle starts with the new stuff and the others use up the dregs. The cans are marked so I don't stuff it up.
I had considered the possibility of deterioration Nick-D. I just had a look at the original powder can and it seems to be marked 91 which may be manufacture date. The original powder had been sealed up in loaded cartridges and not exposed to excessive heat. Additionally my records yielded chronographed data for the same 120 grain projectile load with the original powder from 1993 at 2,781 fps v 2,805 fps the other day. The earlier data was shot in an M38 6.5 x 55 mm using the same chronograph but with an eight foot screen spacing. Google was also consulted which turned up a post on one of the US Forums reporting an increase in burning rate of H4350 of about the same magnitude as I was finding. This was posted about 2002 from memory. This together with the differences in load data between Hodgdon (ca 1995) and Nosler would indicate that the change in speed is real.
Many thanks for your comments and regards,
Grandpamac.

Interesting !
What was your SD for the two loads?

Greetings JaSa,
The original powder load shot in 1993 was one of a string of three loads from 46 grains to 48 grains of AR2209 with the 120 grain projectiles. only two rounds of each were fired. I was running the printer at that stage and the results were as follows: 46 grains 2,781 fps average, 32 fps ES, 22 fps SD. 47 grains 2,855 fps average, 1 fps ES, 1 fps SD. 48 grains 2,923 fps average, 10 fps ES, 7 fps SD. These were fired in my M38 which had a 600 mm barrel in reasonable condition. The load fired this week was: 46 grains 2,805 and 2,807 for an average of 2,806 fps. You will need to calculate the SD for this one. This was fie=red in my T3 with a 565 mm barrel.
48 grains of AR2209 with the 120 grain projectile is above maximums current today but was below the 49 grains of IMR 4350 listed in the Speer no 9 and other manuals of the time. Other information I had suggested that AR2209 was slightly slower than IMR 4350.
Regards Grandpamac.

This is just so funny I thought I post it here:

Just cracked open a new bottle of AR2209 and loaded up some 143gr ELD-X for the 6.5CM and went out to the farm. Lined up the first steel plate which is 433m away and is 31 clicks up - and missed way to high. Had to dial it back down to 28 clicks to hit the 20 x 20cm plate. Done some groups at 200, 300 and 400m on a sheet of ply and they suggest that the speed went from 2500fps from the old bottle to 2605fps with the new bottle. Changed the speed in my App and lined up the 615m plate - hit at first shot.

Will definitely mix all the bottles from now on to average out the different batches...

An interesting post JaSa.

Q.E.D.

Sorry, couldn't help myself. For those of you who did not experience or have forgotten late secondary school mathematics Q.E.D. is an acronym for the Latin Quod Erat Demonstrandum. Very roughly translated means thus it has been demonstrated or as we were told all those years ago at school all that was set out to prove has been proved. Seems to be appropriate here.

I'd be interested to know how old your earlier batch of powder was. My tin, yes it is in a tin, is lot MEN 3689 Packed 0100. On the top the tin is stamped APP 98 which may indicate 1998 or may not. The tin and label style is that shown on the ADI 2000 printed Guide.

Regards Grandpamac.

For Widerange,
Grandpamac.

I use 2208, purchasing large (10 or 20 kg) lots so I don't change batches often.
(We use between 10 & 15 kg a year)

The last time I had a batch change in 2208 I loaded 24 rounds with the old batch, 24 rounds with the new batch - everything else the same.

Off the the range.
Test fired 12 of old, let rifle cool then 12 of new.
No noticeable difference in velocity or group.
Shifted to a longer range repeated firing new then old.
No noticeable difference in velocity or group.

Conclusion same load will do, the nut behind the bolt is the biggest source of inaccuracy.

Greetings Cyclops,
I don't use much AR2208 but AR2206H and AR2213SC have always had minimal differences from lot to lot for me. Thus I was surprised to see the variation with AR2209. All the loads I tried shot close to one point of impact at short range at least but JaSa found considerable differences in elevation at longer range. Without a chronograph I wouldn't have spotted the difference. I pretty much use your system of checking but with rather less rounds.
Regards Grandpamac.

I havent had a problem with ADI powders but then I havent had any that old to compare to either.
Superformance on the other hand can go from safe to overload from one bottle to the next purchased at the same time but different lot numbers.

This mirrors my experience exactly.

Both my .243 Win and 6.5CM shot high on the drop tests when I started a fresh batch. The old batch was 2012, the new batch 2019. Velocity increased about 70fps on both rifles.

However the new batch was laser accurate in both rifles so I got in touch with Rob at Workshop Innovations and he organised me a bulk shipment all from the same (new) lot, which will last me a good while. I now also use it in 6mm Creedmoor.

Interesting thread and well suited to a campfire and beers. I have oft puzzled over poi changes between okd and new loads. I've decided that such things as slight changes in neck tension due to ageing brass or different brass lots or numbrr of times reloaded, primet batches. and seating depth are all potential factors. I have for instance measured up yo 5 thou" chsnge in seating depth simply between v cold winter temps and hot summer temps affecting expansion of the press itself. I have also measured differences in bullet dimensions like length, base to ogive, ogive to point, cannelure position between batches of same brand. Even weight variances within and outside lots. Nowdays I try to mitigate these variances by various simple means , often "dead reckoning" and then accept that a couple of medium range foulers to check zero before a serious hunting trip are a good idea. Of course, at a range comp you have two sighters anyway, and there are good basic reasons for that allowance.