99 grains of H870, chronographed 2978 on an 85 degree day. Three shot groups averaged .75" at 100 yds with a small just under 2/3". That's with zero case prep on new Remington cases (dented necks and all ), no messing with seating depth (magazine limited to 3.60") or other powder charges. Also, my bench/sandbag set-up is far from ideal. There's potential for even better accuracy with a more solid set-up.

I think I'm ready for whitetail season.... There's nothing that builds confidence in your rifle and your shooting better than whackin' the gong at 700 yds.

The rifle is a 26" A-Bolt with factory original barrel (originally 300 Win Mag rechambered to RUM).

I was hoping to post some 180 loads as well, but my chronograph took a crap and I ran out of time. I got up to 114 grains of H870 with the 180 XLC's and Sciroccos with no pressure signs. They must have been smokin'!

[Forgot to add a disclaimer..... This load is max but safe in my rifle. Reduce by 10% and work your way up...or blow yourself up!]

[ 08-11-2002, 00:38: Message edited by: Jon A ]

Jon,try 80 TO 83gr of RL25.I shoot 80gr in my Light gun and and 83gr in my Heavy gun.Both will shoot single digit ten shot group's at 1000 yard's.Both will shoot 5 shot's in the .2 range at 100.

[ 08-11-2002, 07:46: Message edited by: Boyd Heaton ]

Thanks Boyd. I'll give those a try when I get the chance. What velocities are you getting?

Jon,I am getting 2915fps with the 240's.BUT these are light load's in my gun's.Am also working with Retumbo.I have gotten 3160 with 220's.Have not pushed the 240's yet....Start at about 82gr of the RL25 oR Retumbo and work up from there.....I think you will like both of them...E.S. with the Rl25 is 7fps over 10 shot's with my light gun.And 10fps with my heavy gun....

[ 08-15-2002, 18:51: Message edited by: Boyd Heaton ]

Figured I'd update this. When H870 ran out I was unable to find a suitable replacement until now. Retumbo was just too fast for this combo, topping out at about 2850 (but accurate). H50BMG would do 2900 but accuracy sucked.

Finally, enter US 869! First time out (also with a new 3-groove 26.7" Lilja) the range was too busy to want to hassle with the chronograph, but the initial results looked good:



Since I had a nice 5-shot group there already, I fired the 101 and 102 grain loads into a different target. They would have opened the group little, if any. I expected to see a pressure sign at or before 102 but didn't.

Then I chronographed one round each at the below charges. It was right at 70 degrees, chronograph was a Oehler M35 about 18' from the muzzle:

102 2971
103 2978
104 3023
105 3075 (slight pressure signs)

I shot one three shot group at 103 grains:



Average velocity, 3007 fps.

While I was surprised with the slickness of the new barrel, in the end this powder performed exactly as I had expected (or hoped) it would for this application. It'll easily match the speed, consistency and accuracy of H870. It'll beat Retumbo by a good 100 fps with this bullet. If it's nearly as temp stable as advertised, that will be a very valuable bonus (one reason I've shied away from WC872). The density is great of you've ever tried H50BMG--even the with the 104 grain load, the powder would still shake in the case even with the long 240 stuffed down to a 3.60" OAL (with fireformed cases this time). In short, a perfect replacement for H870. It's everything H870 was but better (H870 was pretty temp unstable), at least in this application.

I'd expect the typical 26" 300 RUM to top out around 99 grains in the 2950-2975 fps range with this bullet. My barrel is really slick and it's likely most will top out ~2-4 grains less than mine so work up!

Some more data. While it wasn't my intention to conduct a scientific test of temp stability (or I obviously would have kept everything the same), I did want to double check the 103 grain load in warm weather (it was about 20 degrees warmer this time than last time I chronoed them) but I also changed the seating depth by .020". So the difference could have come from either one or a combination of both. Anyway, here are the final results:

I ran six rounds over the chronograph at 103 grains. Average was 3031, which is a bit hot. Those that were at or under that average probably wouldn't be a problem. It's those that are over that are. A couple were over 3050 which is obviously too hot. But here's the worst part--in both three shot groups, two landed in under 1/4 MOA. But in each case, the round that chronographed the highest was a flier about 1 MOA from the first two--which is what one would expect when the pressure gets that high.

Since I'll stick to this seating depth and most of my shooting this summer will be at 85+ degrees, I'm going to knock that load down two full grains, to 101. That should put me in the 2970-2980 range (at 80 degrees at least) and give me a nice healthy margin for hot days.

Keep in mind, I never expected this powder to be 100% temp insensitive (I still can't say with any certainty that it's not), just better than H870 and WC872 (which isn't too difficult). But I think using some common sense as the summer heats up is probably a good call until proven otherwise.

Also keep in mind H50BMG would have been popping primers at those velocities...and Retumbo likely would have been blowing cases. And neither of those is 100% temp insensitive either. So, I still feel US 869 is working perfectly for this application. Nothing else comes close.

I'm currently investigating having my 30-338 Win rechambered for the 300 RUM but the barrel is a 1-10" twist and Sierra recommends a 1-9" twist for the 240 gr. MK. What twist are you using (and seems to work quite well I might add) Jon A? I'm guessing a 1-10" twist was on the Browning but not sure what you had Lilja make you. Are your bullets moly coated or naked? Thnaks ahead of time for the information.

The new barrel is a 1:9. While I do think it is better suited for the 240, the main reason I went with the 1:9 was I'll be shooting even longer, heavier bullets in the near future that would definately be too much for the 1:10.

However, the original factory 1:10 barrel (that was a 300 Win rechambered to RUM) did very well with the 240's. In fact, I shot the best groups ever from that barrel with the 240's. I'd say the chances are very good that the 240's would shoot well from your barrel, the farther you shoot the better they'll do compared with other bullets. No guarantees though, as I do think 1:10 is pushing it for this bullet...and a barrel advertised at 1:10 doesn't always measure out at a real 1:10.... But this is a combo many besides me have used extensively, and most have great luck with it.

I'm shooting the bullets nakid.

Jon A. - Just for your information and anyone else out there whom might be interested, I performed a velocity test with 8 very slow burning powders to see how much of a difference there was between them in preparation for my upcoming loading session for the 300 RUM and 240 gr. Sierra MK. Here is a list of the powders and the 3 shot velocity average I obtained at 10' from the muzzle with an ambient temp of 80 degrees F (listed from fastest to slowest).

Retumbo 2894 fps
N-170 2850 fps
8700 2698 fps
50BMG 2621 fps
IMR5010 2590 fps surplus
WC-860 2544 fps surplus
US869 2478 fps
WC-872 2477 fps surplus

Not sure which powders you've tried in the 300 RUM with the 240's but thought I would give all of these a try even though you are having great success with US869. Anyone have any thoughts about my findings?

What were the charge weights? Some of those velocities are scary low, especially with the slowest powders.

These velocities were from my 30-338 Win Mag and not a 300 RUM. I'm waiting on the reamer to have it rechambered for the 300 RUM. The barrel length is 30", using 210 gr. moly'ed Bergers and Fed 215 match primers. None of the loads had room enough to shake after bullet seating. The charge was 77 gr. for all the powders. While I can get up to 81 gr. of the ball powders into the case (I would have to seat the bullet out a little more), I could only get this amount of the bulky IMR5010 into my cases. In order to keep the charge weights the same for all powders, I went with this lowest charge weight.
What other powders have you tried with the 240 gr. MK in your 300 RUM?

OK, that makes sense. I misunderstood and thought those were RUM velocities.

I've also tried H870, H50BMG and Retumbo with the 240's. H870 was much like US869 but very temp sensitive and no longer available. H50BMG lagged back by 50 fps or so and wasn't as accurate and it was harder to fit it all in the case (which might have contributed to the accuracy problems). Retumbo was very accurate and very nice to work with, nice to shoot but it was a good 100+ fps slower than US 869.

In the end my 101 grain US869 load runs about 2970 and it's nice and mild, giving me good margin for hot weather/dirty barrel, etc.

The 210s (both Berger and Sierra) aren't a bad way to go either. Their actual BCs come close to the 240 and you can launch them faster. 94 grains of Retumbo gives 3130 from my rifle with the 210 SMK. I haven't gotten quite the accuracy of the 240s from it though, but I haven't played with it too much yet. They sure are pointy little suckers.

With the 30" you should run around 100 fps faster than my rifle.

If you haven't stocked up on brass yet, the Nosler stuff is finally available. I just ordered a small pile from Midway yesterday. Should be a nice step up from the Rem stuff. It better be, anyway.

I had some of the Nosler brass on backorder since mid-July from Bruno's Shooters Supply in Phoenix, AZ. I received mine the first week of August. I only ordered 50 rounds since I had 150 rounds of Rem already. In measuring the neck thickness of the Nosler brass, I didn't find it to be any more consistent than Rem's. I do like having the flash hole deburred and the brass all weighing within 1% of each other. I weighed out all the Rem and then sorted. It was fairly consistent with only 2-3 rounds that were way off the weighted average. I use these as dummy rounds for bullet seating and for setting up my neck turner. My 300 RUM chamber will have a tight neck that will require turning the necks of the brass before they will fit in the chamber. The Nosler's are a little thinner than the Rem's but a few are thick enough that I will have to run all 50 Nosler's through the neck turner to catch the few that are too thick for my chamber. Did you have a match chamber cut for your Lilja barrel or just a SAAMI spec chamber?

I gather then you haven't tried any of the surplus powders. I have quite a bit of all the ones I tested and look forward to testing them out. I will report back once I get up and shooting. The reamer is 3-4 weeks out and then my gunsmith will have to chamber it. He isn't the fastest around due to his busy schedule. I hope to be shooting by 1 Oct or slightly sooner.

Just ordered a 500 count box of the Sierra 240 gr. and had them moly'd. I discovered that the price had jumped some $24 from the last batch since most online retailers were out of stock and new stuff was just manufactured & received.

My chamber is somewhere in between. It isn't a tight BR chamber where I need to turn necks, etc, just to chamber rounds. But it's a lot tighter than the typical factory chamber, with a shorter and smaller diameter throat. Fired rounds end up showing 1/2 grain less capacity in the same cases as they did in the "factory style" more sloppy chamber.

I did pick up a big jug of WC872, which is very similar to H870/US869 but never tried it once I heard about US869 comming out. Everybody who has used it agrees it is so extremely temperature sensitive that you really need separate winter/summer loads. I can deal with a little temp sensitivity but that much could get old really quickly.

I just read over on another forum where a guy was using US869 in a 300 RUM and tried it out when the temp was 105 and gained over 100 fps from when he shot the load at 80. His opinion was that US869 is very temp sensitive. Have you had any more experience with US869 in varying temperatures in your 300 RUM?

Still don't have my rifle chambered for the 300 RUM. The gunsmith does have the reamer but recently purchased a new house so funds are a little tight. Gunsmith wants $100 to do the rechamber job. Hoping to have it done fairly soon. I sent you an IM but you can post the response here if you like. I didn't find this post until after I sent you the IM.