whats your thought 7828 SSC & 300 Wtby with 200 gr Part & AB

[284allways]

Gents I took advantage of the good weather today and hit the range with some new loads and discovered some data I wasnt expecting.
200 gr AB in 300 wtby
81.5 gr 7828 ssc a mid range load in the Nosler Bible, fed 215 and Virgin Norma brass.
- the bolt was sticky on a few rounds
- the primers were moderately flat I could still see they were not filling the cup recess
- the fps average was 3,071 with e/s 28 fps for 6 rounds
- accuracy for 2 - 3 shot groups 1-1/4 x1/2 (horizontal) and 1" x 1/4 (vertical)

200 gr Part in 300 wtby
81.5 gr 7828 ssc a mid range load in the Nosler Bible, fed 215 and Virgin Norma brass.
- the bolt was less sticky on a few rounds
- the primers were moderately flat I could still see they were not filling the cup recess to a lesser degree than the AB
- the fps average was 3,053 with e/s 46 fps for 6 rounds
- accuracy for 2 - 3 shot groups 1-3/4 x3/4 (2 shots in 1/4 same POI as second group - this would be a 5 shot group of 5/8 x 5/8 !)[/color]

Next steps
1- reduce to 81.2 grs and re shoot ? Any other thoughts ?
2- he old load was 84.0 of older 7828 (not SSC) this is a surprising big difference in reportedly identical powders !

 

[Guy Miner]

Sadly, powders can differ considerably from lot to lot.

I haven't worked with 7828 in at least 25 years. It was good in my old 300 Win Mag with 200 grain bullets. Didn't have a chronograph in those days, but it was accurate.

3,000 fps seems like it should be a very attainable velocity with the 300 Weatherby Mag & 200 gr bullets, without the sticky bolt lift.

Ya, concur with dropping the charge a bit and re-trying. However, perhaps it's time to try a different powder? 7828 has been around for a long time, and I wonder if there are better options now?

Regards, Guy

 

[Guy Miner]

We have a couple of Weatherby enthusiasts on this forum, and I expect they'll be here shortly with more specific advice.

Guy

 

[flyingagg]

My current 300 wby hunting load is 200 AB with RL22. I never reached the 3000 fps mark.
My old hunting load was with 180 BT and IMR4350. It was extremely accurate, was max in Lyman 46th edition, deemed unsafe in current loading manuals. Did not have a chrony back then, but Lyman listed it at 3194.
My current 180 gr is with Barnes TSX and IMR7828, WBY cases, CCI Large Rifle primer. I get 3091 on hot days.
Since 300 WBY is one of my favorites I am interested to hear what others have tried

 

[FOTIS]

Different lot # powder

 

[str8meat]

83 grains H1000 200 grain accubonds. 2890 fps 300 weatherby marks v 26” tube

 

[Guy Miner]

That will hunt. :grin:

 

[284allways]

Update. lowered to 81.1 of 7828ssc and my velocities went up
-With the Part from 3,053 (first outing) to 3,096 fps and a 3/8" & 1/2" group and still had flattened primers 18 fps e/s
-With the ABs from 3,071(first outing) to 3,109 fps and 1-1/14 groups "some" sticky bolt lift on one round and flat primers 23 fps e/s
Dropping some more in charge weight ...4/10 ths of a grain didn't do it !

 

[SJB358]

So, here is what I would try if you wanna keep working with 7828SSC.

Drop down to 79 grains, load 10 cases up in .2 grain increments and just shoot them over the chrono with each bullet. Record the velocity with each shot. Out of those 10 shots, I'd bet a dollar you'll see a node where the charge weight doesn't meaningfully change the FPS. When you find the node where the speeds stay relatively static within reason, go back and load a group of 6 rounds with the middle charge and see where you end up. You're load will likely be very consistent from day to day and accuracy should be excellent day in and day out since its exiting the barrel in the middle of a node so it gives you a little leeway. Good luck!

I think I use 83 grains for 3075 FPS with a 200 Partition with my son's 300 Wby. Shoots real darned well and since I have 10lbs of the stuff it it'll be awhile before I have to recheck my nodes.