300 rum load development

[Rando]

I have hand loaded for my 300 RUM for 10 years or so and tried several recipes. I ended up with 94g Retumbo, getting 3,200 FPS (215m primers, 180g Sciroccos). No pressure signs. Way back when, this was within acceptable limits, but Hodgdon now lists the max at 92g, so you probably want to stick with that (or less). The powder, excellent. Accuracy, excellent. performance in the field, excellent. The only problem is that the rifle and ammo is capable of so much more than I have asked or ever needed in the field!

 

[WoodswalkerPNW]

I have a Winchester Model 70 in 300 RUM and just picked up a Remington 700 in 300 RUM and a batch of once fired Federal Premium brass. I have Nosler 220 Grain Partition Semi SP, Caliber 200 Grain Partitions and 180 Grain E-Tip Banded Bullets along with a batch of Nosler 300 RUM brass and a BUNCH of RL-25 to work with. I need to get online and figure out where to start.

I see a lot of folks using Retumbo and/or H1000 and/or IMR8133. I don't want to get a whole nother set of powders. At least not immediately. I reload for a LOT of calibers and the powder locker is kinda full already.

 

[Harvey Durham]

Pretty much all the loads I've shot with this gun have an ejector mark. I'm not sure why... I did get slight bolt sticky and bad primer crater at 91 so I consider this max.

A couple things, I think you a little hot on it and have you considered getting your firing pen bushed?

 

[Hookturnr]

I'm on my second 300 RUM barrel, first was a sendero this one is a sendero contour Hart at 27 1/2". Both have been best with a 210 VLD at 3060FPS. Retumbo was the magic sauce in the first barrel and H1000 is now my main squeeze. This is in Norma and Nosler brass with federal LRM match primers.

 

[greatwhitehntr]

I would full length size bumping the shoulder back 2 thousands trim a thousand shorter than trim to length as recommended above. Use a new case from the same lot and measure the web/case head and see how much it's expanding to you're fired cases. I pepersonally hate nosler brass. I've had nothing but issues with it in a lot of Magnum cases. It is way too soft. I've actually had it show signs of pressure from factory ammo at 40 degrees in two different Magnum cases. Some of your primer flow is due to oversized firing pin hole. Depending on what action you have you could have it bushed rather easley. That picture of the brass looked a little hot. Personally I would stick with RETUMBO or the IMR8133 I would use ADG brass or Remington. GUNWERKS is also making 300 rum brass A buddy of mine gave me 20 cases then it is ood stuff. You heard it boys I said it Remington over that shiiiity nosler brass.
If you're still having issues you could take it to a gunsmith and have a chamber cast done and have it scoped and the headspace tested I would do that as the last resort.

 

[DoubleGobble00]

Thanks for all the info. I'm not sure where to start on responses. Overall, it appears I need to FL size to have room for my brass to expand to the front, possibly try H1000 or Retumbo for more velocity, and shoot further of course!

This gun has a 29" barrel so I expected more velocity. It has about 60 rounds down the tube. It's a McGowan barrel and rem 700 action. I can check headspace with my go gauge.

I'm trying to get the 230 to work since they have highest BC. I have the 300 win for shorter ranges. I really want to get over 3k with 230s. Currently I've avoided Retumbo due to pressure spike stories but maybe it's not that bad.

 

[whirlwindjml]

The remmy brass I had could only be shot 2 as opposed to norma which was well worth the wait and $.

 

[DoubleGobble00]

I can change head space if needed. This is a remage build. I have the gauges to check it. I do typically set the head space pretty tight.

 

[whirlwindjml]

The remmy brass I had could only be shot 2 as opposed to norma which was well worth the wait and $.

I believe with a 29" tube you can get plenty velocity with retumbo and not push it to the borderline pressure. I jave had spikes but its always hot barrel @80 degrees and I was at max load.

The h1000 may do just as well I think better if it does work.

 

[tbrice23]

I can change head space if needed. This is a remage build. I have the gauges to check it. I do typically set the head space pretty tight.

Lol, that would have been useful info earlier.
I'd still try to FL size the brass.

 

[greatwhitehntr]

I had a West Texas ordnance switch lug in 300 rum that I had the headspace set really tight on and I'm pretty sure that's the reason why the Remington brass stayed alive as long as it did I will say there were extremely bad lots of Remington brass

 

[whirlwindjml]

I had a West Texas ordnance switch lug in 300 rum that I had the headspace set really tight on and I'm pretty sure that's the reason why the Remington brass stayed alive as long as it did I will say there were extremely bad lots of Remington brass

Many its better now. I couldn't stand digging primers out of the action.

 

[greatwhitehntr]

Maybe I missed it somewhere, what is your cartridge overall length?

 

[DoubleGobble00]

First unless the brass was fired in that rifle, you should full-length size it. Neck-size only if/when that brass is staying exclusively with that launcher, otherwise you are creating potential for pressure signs. Granted some of those signs MIGHT be false readings if the bolt is hard to close, but IMO this is not the caliber to get too frisky with!

Second, yep you probably have either pressure issues or a bad fit in the chamber...head spacing? Better back off that load by reducing powder charges. In this cartridge, I have no doubt you can tighten that group up but if those primers keep doing that I recommend a trip to a gunsmith for a check on your headspace. Also - make sure that chamber is REALLY getting cleaned all the way. At typical RUM pressures it doesn't take much "varnish" build-up in the chamber to start screwing with your headspace, and then reading pressure signs gets tricky.

Third, a question - what other bullets/bullet weights are you planning to try with this rifle? I have not spent time with the 230 bergers in this cartridge, but would like to share this thought - decent 190-200 grain pills are devastating on elk, with 1/2 MOA accuracy out to 500+ yds when I launch them at about 3200 FPS. No pressure signs when doing this therefore I'm comfortable saying that I'm not wrecking my brass either! Note that I use this caliber to hunt, not shoot 1000 yard competition...so if that's a serious consideration disregard and concentrate on the heavier pills.

This is the only Rum I own so the brass does stay with the rifle. The bolt is tight but not too tight. I think my head space is too tight.

I was hoping to stay with 230 to maximize long range potential. The only other bullet I'd like to shoot is the 245 when available.

I hope to make this a 1000 yard gun, use my 300 win mag for closer, then 308 for under 400.