300 rum load development

[Buzzsaw]

wish you were close to me, I have 6lbs of VV-570 I'm selling since I sold my 6.5 Weatherby mag.

 

[Doginab]

I shot my first rounds of hand loads this weekend for my 300 Rum. I loaded the following:

Nosler brass (first 5 new brass, others 1x fired)

215 M primers
Imr 8133 (88.5 to 91 grains)
Berger 230
Neck size only

The 89.5 and 91 loads had primer cratering bad. All shots had ejector marks and slight crater. I'm thinking my headspace is too tight that could cause this? My brass is pretty tight when chambering. All my factory ammo shows ejector marks also. I was hoping to get more velocity since I have 29" barrel.

On separate note, which do you think I should start next steps of load development? Also, if I full length size could I get more velocity and lower pressure?

Thanks,

DoubleG

I went with 96.5 gr. If RL25 and a Fed 215 pushing a 180 TSX from Rem brass. The stock Sundero will clover leaf at 100 yds.

 

[del2les]

Try Retumbo.

 

[Scratch]

Gentleman
What are your starting load suggestions using RL-33? And Primer?
26" barrel
230 Berger

Thanks

 

[Wedgy]

As stated you need to FL size bumping the shoulder back ~.002" or you will have trouble chambering. I was running the 230 at ~2980fps with 89.9 g Retumbo at mag length.

 

[Cross C]

I have worked up 3 different barrels chambered in 300 RUM for my Dad's custom builds. All have been on Stiller Predator LA with Seekins 300/338 long BDM, so these lengths are a little long, but still you could fit them in a CIP length BDM i believe.

Retumbo has been excellent each time, just lancetkenyon suggested above. Super stable with the various Temps we see in Wyoming. Great groups when you find the nodes that the 230 likes, the challenge was finding the top end as you suggest because factory lengths with the RUM are so pedestrian. I had good luck using the Optimal Charge Weight test and then fine tuned with 3 shot groups from there.

I found that 90.00 was our max at 3.100" ogive length with new Norma brass. The previous barrel we had some older Retumbo that must have been a little slower burning and 91.7 was max pressure at about 70 deg outside with Nosler brass. Fed 215 primers in both loads.

With the load we settled on with the new Beanland build on a 28" proof bbl we are at about 3095 avg fps with the Retumbo and the Berger 230s which is CRAZY at 6000 ft elevation.

I'm glad to see RUM threads here now and again! Good luck with your tests.

 

[Chamberman]

wish you were close to me, I have 6lbs of VV-570 I'm selling since I sold my 6.5 Weatherby mag.

Where are you located?

 

[whirlwindjml]

Where are you located?

It stinks when the powder you have doesn't pan out to what you hoped but my experience has been retumbo best as well in RUMs. @ 80 degrees it starts gaining velocity and pressure I noticed. So for hunting it hasn't been a problem. I use 210 or 215 berger in the guns I have. H1000 worked good to but retumo was more forgiving. I keep my freezer full of meat and my shelf full of retumbo. I try to purchase 16lbs at a time to have the same lot for lapua and rums. If I had a longer barrel than 26 inch I would have been able to get a velocity I liked out of h1000 and I would have used it.

 

[coyotezapper]

I shot my first rounds of hand loads this weekend for my 300 Rum. I loaded the following:

Nosler brass (first 5 new brass, others 1x fired)

215 M primers
Imr 8133 (88.5 to 91 grains)
Berger 230
Neck size only

The 89.5 and 91 loads had primer cratering bad. All shots had ejector marks and slight crater. I'm thinking my headspace is too tight that could cause this? My brass is pretty tight when chambering. All my factory ammo shows ejector marks also. I was hoping to get more velocity since I have 29" barrel.

On separate note, which do you think I should start next steps of load development? Also, if I full length size could I get more velocity and lower pressure?

Thanks,

DoubleG

No experience with 300RUM but Quickload shows Retumbo to be "the powder" and the pics by lancetkenyon seem to verify this.

 

[Chippewa]

I have always had crattering with my Ridgeline Rum. But with load ladder would finnally get ejector marks at the upper end. I fl size bump .002" so never have issues loading. Never had sticky bolt but only pushed load so far.
212g eldx
Norma brass
90g H1000 at 300'alt = 3050fps
26"barrel
High Pressure at 91.5g @ 3125fps

I also tried RL25 but was only grouping around 1moa. Now just fire form with that powder. Sounds like vv-n570 is great option if you can find it....

 

[stevers75]

I am going through the exact same thing you are. I started with 86.5 grains of RL 26 for 230's had 3050fps with bad ejector marks. I dropped down 2 grains and and still had ejector marks. Dropped to 83 grains and actually broke the ejector! So I'm waiting for my bolt to be sent back by my smith so I can start at a much milder load and work my way up. I have a 1:10 twist, wondering g if I should switch to 215 hybrids...

 

[ig25]

Yeah I agree that the velocity and group looked best with 87-88.5. I was planning to reloading a few sets of 3 in this range or do 87, 87.2, 87.4, etc mini ladder test.

I was just expecting more velocity before pressure. I have some H1000 I could try or just buy some RE33 or Retumbo

Retumbo is number one in my 300rum
H1000 is a close second. Both shoot 210 Berger's or Amax nicely.
My speeds are out of a 30" tube
208 Amax 3205
210 berger 3189

 

[coyotezapper]

I am going through the exact same thing you are. I started with 86.5 grains of RL 26 for 230's had 3050fps with bad ejector marks. I dropped down 2 grains and and still had ejector marks. Dropped to 83 grains and actually broke the ejector! So I'm waiting for my bolt to be sent back by my smith so I can start at a much milder load and work my way up. I have a 1:10 twist, wondering g if I should switch to 215 hybrids...

RL26 does not give a good fill ratio in the 300RUM. 83 grs is around 86% fill and QL shows it to be not well suited for this bullet cartridge combo.

 

[whirlwindjml]

I am going through the exact same thing you are. I started with 86.5 grains of RL 26 for 230's had 3050fps with bad ejector marks. I dropped down 2 grains and and still had ejector marks. Dropped to 83 grains and actually broke the ejector! So I'm waiting for my bolt to be sent back by my smith so I can start at a much milder load and work my way up. I have a 1:10 twist, wondering g if I should switch to 215 hybrids...

I had easiest Time with hornady 208 grains. The 215s are great but I shot way more bullet s trying to get results I liked. Both were acceptable with retumbo. The 208s shot well with almost any tweaking I did. That was my experience anyway. In hindsight I would have stayed with 208s although the eldx was not out when I was dumping time and cash into the RUM situation.

@ the time I was trying to get the most and beyond 1000 yards. Now I am over it. 208 eldx would be fine or any good shooting one since I believe (for me) 800 yards is as far as I can ethically harvest animals.