Just back from Oklahoma where I broke in my new 338RUM. I used some 'pull-push' loads and shot very well. I used the Remington factory 'hunting' load of 250 Core-Lokt, pulled the factory bullet and replaced it with the 250 Sierra GameKing (I didn't have any 250 MatchKings). The BC on the 250 Core-Lokt bullet should be about .420 according to my 'back-figured' BC. The Sierra 250 GameKing has a BC of .570 or there-about. I checked the bearing surface and diameter and felt safe with the 'pull-push' load.
The factory Remingtons have 90.0 grains of some powder and I get 2903 from the 250 GameKing. There seems to be some room for improvement in the velocity arena and the case was not nearly at 100% load density.
BTW, I used 4 rounds for velocity checks to get a ballistics chart (41 yards into a backstop on the scope installation day). I then drove to Oklahoma and used three rounds for the 100 yards zero. My next round was at 900 yards on a 19 x 36 silhouette from SWAG (guessed) data (2/3 the normal 308 come-ups) as I had left my ballistics sheet in the room. I had a miss, high, came down 2 MOA for a center mass hit (21 MOA). My next round was a POA/POI hit at 1000 yards with a 3 MOA come-up.
I fired an additional 10 rounds to get the short range data, backing down from 700 to 200. I played a little on the shorty (19x18) targets at 400 and 500 yards.
George Gardner was there with his 338 Lapua Mag, it's a good deal 'bigger' than the 338RUM. He was shooting 300 grain MatchKings at just over 2900 fps and hitting the steel pretty hard.
Now.... I need to get serious and load some proper bullets. I know I won't get 338 Lapua Mag speeds but I need to reload some decent rounds for 'plinking'.
Who has some load data with 250's or 300's and Reloader 25 or other appropriate powder?
Before there was any published data I did some testing on H-1000, RE-25 and IMR-7828.
I used Speer, Nosler, Sierra Gamekings, Hornady and Swift 250 grain bullets and accuracy and velocity considered, I settled on Reloader-25.
Depending on powder lot, seating depth and bullet I ended up between 91 and 94 grains.
The rifle was a stock Remington 700 BDL-SS (26inch barrel) in a HS Stock and a Timney trigger. With the typical long factory throat, and the bullet set out as far as the mag would allow it was still a .090"jump to the rifling.
I don't do the long range thing. Yet. I ain't good enough! I settled on the Nosler and 93 grains of RE-25. Accuracy is less than an inch at 100 and velocity is 2950fps.
I have never been able to get much over 2950 without pressure signs. I did hit 3000 with one lot of H-1000 but it was a hot load and accuracy wasn't there.
The gun wants to shoot, using Sierra or Hornady bullets and seated way out towards the rifling I shoot several several sub half inch three shoot groups. Smallest was .187".
Anything I can answer, let me know, Joe.
Now I have a mystery going, Darryl and Warren, what am I seeing here?
exerpt from an e-mail I sent...
More data today, RL-25 data but data none-the-less.
Rifle Tac-Ord 338 RUM
Barrel PacNor Polygonal 27.5 inch 1x8
Scope Leupold Vari-X III M1-LR (3.5 x 10 )
Chrony @ 8 ft
Target Distance 100 yards
Primer Fed 215M
Case Remington once fired and neck sized
bullet runout - minimal .001
OAL 3.650 (Same OAL for the Sierra 250s)
Bullet Sierra 300 HPBT
I don't know why I have the "extractor" mark on the 85 grain load, I've examined the other loads and I see ever-so-slight extractor marks on the 87 grain load but nothing on the others (I use a 3x, 5x, and 8x jewelers loupe). There is some cratering around the firing pin on the cases but I believe that's due to the looser fit of the Speed-Lock firing pin I have.
I'm a bit perplexed by the powder requirement when compared to the 250 Sierras. I expected to get nowhere near the starting load of 89 grains of RL25 for the 250 when finishing off the big 300s. I believe I'll load several more cases for the 300 load test, I'll use 90, 91, 92 etc until I feel the need to pull the trigger from a distance with a string.
The 300s sit a fair distance into the case, the boattail is below the level of the shoulder at an OAL of 3.650.
Accuracy.... I nearly wet myself!!! I mentioned to you yesterday how I shoot onto one target and plot the hits in an attempt to limit my range trips for accuracy loads. Well, today I began plotting the hits (1.5 MOA low and .5 MOA right from my established 250 grain zero) and ALL rounds impacted essentially on top of one another, so much so that I couldn't distinquish one hit from another. Final group-- .863inches for all 10 rounds of 10 different powder weights. It's just a round raggity hole, I'm pretty pleased.
BTW, today I shot at my usual spot, a farmers field into a bank for a backstop. Shot from the bipod and sandsock, much more natural and comfortable.
I believe I'll be able to get 2700 without a problem but not much more as I'll be on a compressed load. Perhaps the RL22 is the better way to go for the 300, I could perhaps get another 4 grains of powder into the case if I'm thinking correctly.
I'd guess that the powder quandry is that the RL25 is better suited to the much heavier bullet in the larger .338 bore rifle, although RL22 could offer more usable powder it may cause some pressure curve problems. Maybe I should try the RL22 in the 250s.
Dave you may find that, the 300 gr will be your best compititive bullet to use.
At 2700 FPS in the 27" barrel that, is doing just fine.
To bad the throat in you rifle is not extended enough to seat the bullet out further.
A friend of mine at Williamsport has a 340 Weatherby imp. and with his 34" barrel,puts 92 gr of 25 in with the 300 gr bullet. He is doing VERY well with it too.
My load in a 340 Lilja IMP (340 case) rifle I use to shoot was also 90 to 92 grs of 25 or 5010. It did quite well with either powder.
Why extractor marks half way up your test list of powder?????????? Excess head space with THAT case? Bumped the shoulder back to far? I did run into a batch of 300 gr bullets that were just a bit OVERSIZE in the diameter. I measured some that were .3380" and went up to a few that went to one or two that were .3385". Talking to Sierra folks, I found that the allowable limits are to be up to .3384" on that bullet. You may have had a slight pressure problem from a slightly bigger diameter bullet. This happens more then one realizes. It's still a puzzle but, an answer can be found.
I think RL25 may be the way to stay with the 300 gr and experiment a bit more with the 250 gr and RL22
Just a suggestion for you.... I've had much beter grouping and chrono numbers using 210 primers over the 215 primers in my 338 Lapua Improved. Have fired the 210 primer as low as 40F. In really cold weather I don't have the experience/data. In my 338 Yogi case I've had better luck using H1000 over R25. R25 SD was close to 40-50fps min/max variation. H1000 is low to mid teens.
Granted the RUM is a little different shape case and different volume so this isn't a 1-to-1 comparison. Just thought I would throw this out for your information.
have you water volumed aany of your cases? If so I would be curious to know what it comes out as. My case is 120.5gr of H2O. This is with the water being level with the top of the neck and an inverted primer cup seated in the primer pocket.
I know that the 300 Rum is larger but here is some thing to compare to. I checked an unfired 27/300Rum, water even with the top of the neck and got 112.6, unfired 300 rum came in at 113.5, and a once fire 300 was 116.4.