300 RUM Loads with the Hornady 208 A-MAX

[Andy]

I recently bought a Rem 700 SPS from "Doug" and I'm still not sure why. I do enjoy large capacity cases and developing loads for them and have a few to share for the 300 RUM.

The Hornady 208 A-MAX is the kind of bullet that can shine in a case like the 300 RUM - heavy with a high BC. What I could found "out there" were plenty of loads using Retumbo and RL-25, but very little with US869 (a favourite of mine).

My gun has a moderately long throat (0.250") and with this bullet, an OAL of 3.850" put it 0.050" off the rifling as I generally prefer. That's ok for single shot action, but the mag can only accomodate 3.650", so I tried the loads at 3.650" and at 3.850" to see how that affected MV (i.e. pressure) - I got a bit of a surprise.

L to R - OAL of 3.850", OAL of 3.650" and the 208 A-MAX The red line marks the throat length

300 RUM, 208 A-MAX, 25C, Rem 700 SPS with 26" barrel

Retumbo

91.0 grs - 2850 fps
92.0 grs - 2950 fps
93.0 grs - 3000 fps
94.0 grs - 3040 fps
95.0 grs - 3070 fps I consider this a Max load

US869

101.0 grs - 2980 fps
102.0 grs - 3025 fps
103.0 grs - 3050 fps
104.0 grs - 3100 fps
105.0 grs - 3130 fps I consider this a Max load

There was still room for a couple of grains more of Retumbo even at the OAL of 3.650", and room for 3-4 grs of US869.

With the longer OAL, you'd usually expect better accuracy (that's TBD) and a different MV. You decrease pressure with the larger effective case capacity, but increase pressure by placing the bullet near the rifling lands. At the OAL of 3.850", with the Retumbo (the faster powder) the MV was consistently higher, but with the US869, it was consistently lower.

 

[LeRoy]

Thanks for the info, Andy.
Did you have any pressure signs with the higher loads?
I was leaning toward Retumbo and RL-25 myself, but have not had a chance to pick up any powder yet.

LeRoy

 

[Andy]

Thanks for the info, Andy.
Did you have any pressure signs with the higher loads?
I was leaning toward Retumbo and RL-25 myself, but have not had a chance to pick up any powder yet.

LeRoy

There weren't any "Pressure Signs", but I don't trust them anyways. The only one I do is loose primer pockets after fewer than five firings.

The Retumbo load (95.0 grs) is max based on published loads. I would likely use 2-3 grs less to where accuracy was optimized. The top US869 load (105.0 grs) is based on extrapolation - it's a much slower powder and for equal MV's, the slower powder will always have a lower peak pressure. If for some reason I wanted to hit a MV of 3200, I'd use US869, probably with 107.0 grs.

I have heard that both Retumbo and RL25 are great powders for the 300 RUM in the 180-210 gr bullet range.

Recoil - I shot 20 shots off the bench and didn't find it that bad. I was also shooting 12 ga slugs, so maybe that made it feel better. I did have to move my Chrony back another 10 ft though as the muzzle blast kept dislodging the chrony's "arms".

I like it, and no longer see the need to own a 300 Win Mag.

 

[rig_pig69]

So in your expreieince, how does the a-max stand up against the 220 mkhp??

 

[Joel]

Great info, Andy! I am building a 300 RUM on a Rem.700 action and thats just the bullet i had in mind.

Thanks for posting.

 

[Andy]

So in your expreieince, how does the a-max stand up against the 220 mkhp??

I don't know, because I haven't shot it and don't know what you mean by "stand up". Accuracy-wise, the 208 AMAX is very good in most guns, but there are better (not that the 208 AMAX is bad) bullets for hunting. The big advantages of large cases like the 300 RUM is with the heavier bullets, and it can handle a 220 very nicely.

Great info, Andy! I am building a 300 RUM on a Rem.700 action and thats just the bullet i had in mind.

Thanks for posting.

That's my main bullet. It's fun to see what you can do with a light bullet velocity-wise (try a 125gr at almost 4000 fps!), but it's the 200+ gr bullets I prefer, otherwise I'd just stick with a 308.

P.S. Joel - get your butt down to our Milshoot. It's on Sat 19 Sept.

 

[TwoTone]

Thanks for posting that Andy.

It's hard to find US869 data and that powder is a very good choice for the 300 RUM.

I've not tried the 208 Amax yet. I did work up some loads with the 200 Nos Accubond but I just couldn't get it to shoot.

I've since dealt with some possible issues with the rifle itself so now I'll have to try them again.

Have you done anything with Accubonds in the RUM yet? They really perform well on game.

______________

Andy - since 1967

 

[TwoTone]

Rl 25

I just tried some RL 25 with the 200 NAB for the first time and so far my rifle likes it a lot better than US869.

I loaded a few with 87.5 gn RL 25 and got three 5 shot groups in the .9's right off the bat. This will be good enough for my upcoming Moose hunt for sure but can likely be improved upon.

This is the starting load in the Nosler manual. Vel. was listed as 3060ish but my average for 15 shots was 3145fps. No pressure indications at all either - Bonus!

I'm quite pleased as I'd previously gotten poor groups with this bullet using US869, some over 4" (yes, at 100 yards). Talk about discouraging...

To be fair I've since bedded the rifle and sorted out some bad brass and am now using a Lee Collet Die which produces cartridges with less than .002" runout pretty reliably ( I was getting some really bad runout using the Lee RGB dies), so I will go back and try US 869 again. However, my load with the 165 NAB hasn't really improved much in grouping since these changes so who knows?.

My MAX load with US 869 got 3274 fps and was also the most accurate at around 1.2".

Recoil: My Sendero in 300 RUM kicks a bit with this load but I had no problem firing 20 with accuracy. I was also shooting a Marlin Guide Gun in 45/70 with a 420gn bullet at 1800 fps and a CZ550 in 416 Rigby with a 350gn TSX at 2650fps. In the recoil hierarchy, the Rigby is definitely king, the RUM is in the middle and the Marlin is the lightest. I started with the Marlin to 'warm up' then went to the Rigby and then relaxed with the RUM to finish.

This was all from my 'poor mans standing bench' ie. the hood of my truck. I doubt I could have done all of this shooting with these guns in one day from a bench. Shooting from a vehicle isn't quite as stable either so I'm pretty happy with sub MOA.

I'll stop rambling now, this thread is supposed to be about 208 Amax's if I recall....

 

[TwoTone]

Andy, are those loads crimped with a Lee Factory Crimp Die?

It looks like it in the photo.

I have one but did not use it in the loads mentioned above.

 

[Andy]

Nope, not crimped, but I can see why you thought that. I don't own a Crimp Die for this round and don't see why I'd use it. A heavy recoiler for sure, but those bullets are held fast by the neck.

 

[TwoTone]

Nope, not crimped, but I can see why you thought that. I don't own a Crimp Die for this round and don't see why I'd use it. A heavy recoiler for sure, but those bullets are held fast by the neck.

I tend to agree. I didn't have any bullet movement on the rounds in the magazine when I was using the standard dies.

With the Collet Die neck tension may be less so I guess I'll find out. Seating force didn't feel any lighter though so hopefully bullets will stay put.

 

[BigUglyMan]

Have you considered trying 210 Bergers? From what I've heard from guys I trust they hold up better on game than the AMax. Mind you, LongRangeCanuck uses the 208 AMax in his 300 WM with great results and Blackcloud uses the 210 Bergers. Rounding out the threesome, ATR Rick uses the Matchking.

Who to believe?

 

[dan belisle]

I use the Amax in my 300 RUM. 96 gr of Retumbo, if memory serves (I'm overseas again and can't check my notes). 3100 fps, decent (but not great) groups. I'll try US869 when I get home. I put a brake on mine (700P), first rifle I ever chose to do that with. Recoils as bad as my 340 Wby or 338 Lapua. - dan

 

[rnbra-shooter]

Interesting thread, thanks!

Sure seems surprising that 1-grain powder increments, in such a big case, are giving such large velocity steps - 50-100fps per grain, wow!

300 RUM, 208 A-MAX, 25C, Rem 700 SPS with 26" barrel

Retumbo

91.0 grs - 2850 fps
92.0 grs - 2950 fps
93.0 grs - 3000 fps
94.0 grs - 3040 fps
95.0 grs - 3070 fps I consider this a Max load

US869

101.0 grs - 2980 fps
102.0 grs - 3025 fps
103.0 grs - 3050 fps
104.0 grs - 3100 fps
105.0 grs - 3130 fps I consider this a Max load

 

[Andy]

It actually averaged about 40 fps/gr which is pretty average in my experience.

You need to realize that these were one shot results for each load, not the average of several. In the example of the two adjacent loads that resulted in a 100 fps jump, I probably had a low result beside a high result.

 

[rar]

im lookin forward to trying some of the berger 210 grain vld bullets in my 300 rum also .