Help with 300 RUM

[aaroncarp]

I have a basically bone stock 300 RUM m700 sps with maybe 180 rounds thru it. I just added a blackhawk axiom stock to help reduce recoil and to upgrade from the cheapy plastic one. Anyways I have had some problems developing a load for it. I know im going to want to shoot berger 210s out of it but right now im developing a load with 208 amaxs.. Im struggling to find a load that will do better than an inch at 100 yards. For what I need, an inch will work, but from what I have read, similar guns are shooting 5/8" groups right out of the box. I am hoping the gun can do 1/2 moa or better.

I have gotten 2 loads to shoot at about an inch, 90 grains of retumbo and 90.3 grains of retumbo both with Amaxs and 3.600" overall length and remington 9-1/2 magnum primers. (i use the gun primarily as a hunting rifle so I will sacrifice a little accuracy in order to fit in the magazine).

Im wondering if I should forget load developing with the amax and move straight to the bergers with the same loads and see if my groups improve. Otherwise, I am new to reloading and any suggestions would be helpful to actually get this load development somewhere. Also, what are your loads that work well for similar guns?

Thanks in advance

 

[ultraedge]

Seating depth can make a lot of difference. Start with your bullet about .005" off the lands and shoot several groups. Then move away from the lands about .040" and shoot a couple more groups. Move back .040" more and repeat. Fine tune both ways from your best test groups. Once your best seating depth is found, you can lengthen the magazine if you need to. Gary

 

[trebark]

ultraedge is right that seating depth can make a big difference. I do think that making .040 moves is too large. Read this thread for Berger's recommendations on making seating depth adjustments:

http://www.longrangehunting.com/for...accuracy-berger-vld-bullets-your-rifle-40204/

Although the 208Amax and the 210berger are great bullets (I shot the 208 in my 300rum too: http://www.longrangehunting.com/forums/f53/my-300rum-mcr-70809/) you should give some consideration to the 230grain berger hybrid.

Also, is your action bedded in the stock? If not, it should be.

Finally, consider changing from the magnum primer to a standard primer.

 

[aaroncarp]

Thank you guys. The stock is aluminum pillar bedded, the action fits very tight in the stock. And as soon as I posted the thread I read the article on shooting berger bullets. My question now is what grain of powder should I do that with?

90 grains seems to shoot the best from what I have tried but I havent gone over 92 grains. When I started experimenting, I did not want to go over the max load in the manual. Now I am reading where people are getting 3100 and 3200 fps and 1/4 moa, with guns that are basically right out of the box, with 94 grains of retumbo and 210 grain bullets. I lost any accuracy I had when I added much more powder than 90-90.5 grains. Is it possible that those groups would shrink back down with more powder? Also, more powder means more barrel wear correct?

And concerning primers, I havent actually read anywhere where people are shooting these remington primers, maybe they are junk? I dont know. I guess I did not figure that primers would make that big of a difference. What primers would you guys recommend shooting? I have a lot of CCI large rifle primers that I load for my 22-250 I suppose I could try those.

 

[aaroncarp]

The other problem I am running into with the A-max is that the OAL is ranging by 3 or 4 thousandths sometimes even with the die set pretty tight. I am pretty confident that is just from the cheesy soft plastic nose on the bullets. But if the OAL was different that would explain why I can shoot two through the same hole then a third shot an inch and a half away. Im hoping with the solid bullet the bergers will give me a more consistent OAL.

 

[trebark]

Thank you guys. The stock is aluminum pillar bedded, the action fits very tight in the stock. And as soon as I posted the thread I read the article on shooting berger bullets. My question now is what grain of powder should I do that with?

90 grains seems to shoot the best from what I have tried but I havent gone over 92 grains. When I started experimenting, I did not want to go over the max load in the manual. Now I am reading where people are getting 3100 and 3200 fps and 1/4 moa, with guns that are basically right out of the box, with 94 grains of retumbo and 210 grain bullets. I lost any accuracy I had when I added much more powder than 90-90.5 grains. Is it possible that those groups would shrink back down with more powder? Also, more powder means more barrel wear correct?

And concerning primers, I havent actually read anywhere where people are shooting these remington primers, maybe they are junk? I dont know. I guess I did not figure that primers would make that big of a difference. What primers would you guys recommend shooting? I have a lot of CCI large rifle primers that I load for my 22-250 I suppose I could try those.

You're right, many people are shooting 94grains of Retumbo in 300rum. My rifle would show pressure signs at 92. The best load was at 91grains. The way you find out if your rifle likes more than 91 grains is to simply try it. Whenever you get a pressure sign (ejector mark, flattened primer etc), just stop. Your top end is below that amount of powder.

In terms of incremental changes, don't waste your time with .5grain changes. Go with 1grain changes as 1% of 90 is .9grains. So test 90, 91, 92, 93, 94. Then once you find the charge that seems to be working well, if you want to try a .5grain change just to see what it will do, give it a try.

Will any of these increases in powder increase your accuracy? there's no way to know until you try. And yes, more powder = increase pressure and temperature which means more wear and tear on your barrel. Don't let it bother you though. You can burn up a barrel with 91 grains just as fast as you can with 94. The key is to not shoot in rapid succession. Shoot and let the barrel cool, then shoot again. How much time between shots? that's up to you and your barrel. I like to give it a couple minutes between shots with the big magnums.

As for primers, I have no opinion nor evidence as to whether Remington primers are junk or not. Personally, I use CCI BR2 and/or Winchester WLR.

 

[trebark]

The other problem I am running into with the A-max is that the OAL is ranging by 3 or 4 thousandths sometimes even with the die set pretty tight. I am pretty confident that is just from the cheesy soft plastic nose on the bullets. But if the OAL was different that would explain why I can shoot two through the same hole then a third shot an inch and a half away. Im hoping with the solid bullet the bergers will give me a more consistent OAL.

Your die is not moving, the variance you are seeing is caused by manufacturing variances with the bullet. I noticed the same thing when I measure my finished rounds. When I want to be meticulous, I measure each one when the bullet is seated and then make adjustments to get each one exactly the same. Although the 208Amax is a great bullet, this variance can be the cause of your not-great accuracy.

Although your rifle may like the 210VLD just fine, you will probably have better luck with the Berger Hybrid bullets. they make them in 215grains and 230grains. The hybrid ogive is more forgiving when it comes to seating depth.

 

[R.Morehouse]

If you want your " Go-To " load to fit in your mag then your load needs to go from there. Don't worry about speed in your hunting rig. 210g will stay supersonic and kill **** way past where you are most likely going to be shooting them. My RUM with a 27" 10 twist last weekend with a mild 88.5 Retumbo and 208 A-Max shooting mag-fit rounds 1) 2998..2) 2996..3) 3002. This gun with just touching the lands pretty much cuts a hole but with the jump required to fit in the mag I am at just under 1/2". The gun is a custom. If I want to shoot mag-fit it wont be my best load. Most likely won't be yours either....I wouldn't go crazy chasing a load. Save the 210's and brass for killing ****.....Good Luck..Rick

 

[aaroncarp]

Perfect, I will look into a box of the 230 or 215 hybrids but first i am going to load some of these 210s up. I will increment them at 90, 91, 92, and 93.. I will see where that goes. Hopefully I will find a load that shoots 3/4" or 1/2". Really all I want is a gun that can shoot and kill accurately at longer ranges.

 

[trebark]

Really all I want is a gun that can shoot and kill accurately at longer ranges.

This is what we all want!

 

[Wachsmann]

aaroncarp,

I started with the 210 and found they were somewhat fussy. I got my best group about .075 off the lans. with 91.5 grains of retumbo. It was about 3050 to 3040 fps.. I had to bump up to about 93 grains to get 3100fps which is over max book charge. I was starting to see ejector marks at 92.7 and at 93 I knoticed a very slight difference in bolt lift on a fired case. But my 91.3 to .5 shot the best. I also use federal magnum match primers. Even then it was at best 1/2 inch to 3/4 inch groups. I went to the 230 OTM bergers and 89.4 grains of retumbo at .75 off the lans, same primer....It shot a .3 inch group at 200 yrds. My gun is a sendero, with the trigger adjusted, beaded, and has a great muzzle brake on it. The muzzle brake makes a world of difference. Also I would not reload my brass past 5 times and this seem to be pushing it. I had a case separation or case breach at the 6th reload. Only on 1 but it was enough to say 5 is max on these cases. Remington brass. Also I full length resize. probably need to start just neck sizing. None of the rounds I loaded to fit the mag gave me the best accuracy. So I use mine like a single shot but eventually I get the extended mag box.

 

[aaroncarp]

Perfect, thank you all for your input.. If there is any more info, keep it coming. My plan right now will be to..

1.) find the OAL that touches the lands, just to know where I am at.
2.) load some 210s at 90, 91, and 92 grains and an overall length that fits in the mag (considering I am kind of set on mag fit... elk can just flat absorb lead and I dont want one walking away)
3.) If I find one of these that shoots .75" or .5" then i will call that a good load for hunting purposes.
4.) If I cannot find one, I will mess with the OAL shorter and longer (maybe .015" increments)
5.) If the VLDs still do not shoot well, I will look for some 230 or 215 berger hybrids. Does anyone have an opinion on which one is better? both are obviously huge bullets with high b.c.
6.) Start from 87 - 88 grains of retumbo and move up from there at a mag fit OAL.
7.) Hopefully at that point I have a load worth something and then I can get it on a chrony and start shooting past 500 with it.

Also, the local sports stores have some h1000 and retumbo in stock. I have like 3 lbs of retumbo but would it be worth trying some h1000 too? or just a waste of money that I could be spending on bullets and brass?

 

[trebark]

Perfect, thank you all for your input.. If there is any more info, keep it coming. My plan right now will be to..

1.) find the OAL that touches the lands, just to know where I am at.
2.) load some 210s at 90, 91, and 92 grains and an overall length that fits in the mag (considering I am kind of set on mag fit... elk can just flat absorb lead and I dont want one walking away)
3.) If I find one of these that shoots .75" or .5" then i will call that a good load for hunting purposes.
4.) If I cannot find one, I will mess with the OAL shorter and longer (maybe .015" increments)
5.) If the VLDs still do not shoot well, I will look for some 230 or 215 berger hybrids. Does anyone have an opinion on which one is better? both are obviously huge bullets with high b.c.
6.) Start from 87 - 88 grains of retumbo and move up from there at a mag fit OAL.
7.) Hopefully at that point I have a load worth something and then I can get it on a chrony and start shooting past 500 with it.

Also, the local sports stores have some h1000 and retumbo in stock. I have like 3 lbs of retumbo but would it be worth trying some h1000 too? or just a waste of money that I could be spending on bullets and brass?

Sounds like a good plan. Here is my one comment:

#5 - You can't really say that one is 'better' than the other. They are different. Before you buy either of them, make sure you have a 1:10 twist barrel as that is the twist that's required to stabilize them. If you do have a 10 twist, and want to load mag length, look at the length of each of the bullets and start with the shorter one. Remember, Berger makes two 230grain bullets. One is their Hybrid and the other is their OTM Tactical. The tactical is the shorter of these two bullets.

 

[aaroncarp]

Went to the range today. I was in a bit of a hurry and havent gotten an OAL gauge yet but I figured I would load up some 210 VLDs anyways.. I set them at the absolute longest I could get them to fit in the magazine (in this case 3.675") loaded 5 at 90 grains, 5 at 91, and 5 at 92. (I do 5 shots because that way I can screw up with 2 of them and still have a good 3 shot group) The 90s gave me a group just outside an inch without a sled. Decided to put the next 2 on the sled and got just under and inch with 91s and then just under a half inch with the 92s. So I think I have found the load I am going to hunt with. I will find someone with a chrony at some point and make some ballistics charts. I dont know if it was the extra 75 thousandths, the different bullets, readjusting my trigger, or really taking my time with the sled that made the difference but my gun shot much better today than it ever has. Once again thank you for all the advice.

Also, anyone know what kind of velocities I might be getting out of that load? I'm really hoping to have that bullet moving faster than 3000 fps? I know the difference in seating depth can affect that.. and the barrel length too (mine is 26" 1:10" twist)