RL33 and 338 RUM WITH 300 GR Accubond

[D.Camilleri]

I have been playing with Rl33 for the past 8 weeks between cleaning out the carbon fouling from my barrel. My load development has been with the 300 gr Nosler Accubond seated to magazine length of 3.670. 100 grs netted 2820, 101 netted 2857 and todays load of 102grs yielded 2895. None of these loads exibited any pressure signs, stiff bolt or ejector marks. This is a heavily compressed load, and the SD on the 101 gr load was 8 as viewed from the Magnetor speed chrono. 101 shot about a 3/4 inch group, 102 was spread right to left quite a bit, but vertical was very good.

My goal was to get to 2900 fps with a 300 gr Accubond and I was able to achieve this goal. Now if I can shrink the group all will be good. I might try changing the seating depth to see if anything changes.

 

[Timber338]

Nice work. That's some impressive speed from a 338 RUM.... RL33 sure gets the job done. I've got nearly the same setup as you do and I am only getting up to about 2800 before I see pressure signs.

i am shooting the 300 Accubond and the 300 Elite Hunter, both with RL33, and they perform nearly identical with velocity and accuracy. I have done some fine tuning with the 300 EH and will likely use that to hunt this year. Both bullets are shooting great at long range but the BC of the EH is hard to beat.

Have you done any temperature sensitivity testing with your setup? I have done several tests ranging from the low 20's up to the mid 60's and pretty well have my system dialed in. My rifle is shooting right at .87 FPS/degF, and it's all been verified with my Magnetospeed and drops out to 1000 yards. I am also getting single digit ES, along with sub 1/4 MOA accuracy. The rifle is a machine.

And this load is only 93.0 grains of RL33. Much less than you are able push. My gun likes a small .010" jump and That makes the COAL of the Accubond 3.795 which just fits into my magazine box. The EH has to be single loaded, COAL is 4.915. Like you have pointed out, the small jump increases pressure, but even if I loaded to a longer jump I still wouldn't get the loads you are getting. No big deal, every barrel is different.

Glad you started this thread, was thinking about doing something similar and then this just popped up! I would really like to hear how your rifle continues to perform.

 

[450hunter]

Keep the good info coming guys, I have a factory 338 RUM. I really wanted to shoot the 300 grn bullets but haven't really had good luck. I'm still going to try though.

 

[D.Camilleri]

For anyone else with a somewhat factory gun, I am using a factory magazine box at least this week. I am seating bullets to just clear which is 3.670. I still have a jump of around .140 to the lands. I tried loading to a deeper seating depth and nothing about it was good. More pressure and less accuracy. I have a load with the 300 grain Berger OTM that is 90 grains of H-1000, cci 250 primers and it nets 2775. I started playing with the 300 grain accubond as a fight stopper round for mad grizzly bears. 100 gr of RL33 got me 2820, 101 gr 2857, 102, 2895, no hard bolt lift or extractor marks. Remmy brass.

Now that I have started with a very clean bore, I need to find how many fouling shots this barrel takes to get it to settle down. I shot around 13 rounds yesterday and the last 3 were Bergers and they were touching. But I don't know if this is due to a thoroughly warmed up barrel or not. I need good cold bore numbers. I think I will shoot again without cleaning and see what the results are. As soon as I am confident of my 100 yard groups, I will take it out to 700.

 

[Timber338]

I was only able to reach the low 2700 FPS with H1000 and the 300 grain Accubond.

My barrel is a Hart, and it likes to be clean to shoot to its maximum accuracy. I only need 1 fouling round and then it's ready to go for about 20 shots. Then I clean again.

I do have an accurate load developed with the 225 Accubond, 96 grains of H1000 shooting at 3150 FPS. It's just as accurate as the others, but the lower BC would prevent me from shooting it long at an elk. I will likely use this load when I am stalking through the forests since it fits in my magazine box.

 

[Pdvdh]

The EH has to be single loaded, COAL is 4.915. Like you have pointed out, the small jump increases pressure, but even if I loaded to a longer jump I still wouldn't get the loads you are getting.

Did you mean COAL of 3.915"?

 

[338RUML]

Perfect thread to keep my eyes on for a while, I also have a Mostly factory 338 rum except for the trigger, I am going to keep my mouth shut and just observe for a little while I was just going to ask you guys what cleaning solvent you use to clean and if you use those copper brushes or nylon brushes? Also how many rounds do you shoot starting with a clean barrel until you clean it again? I am using a nylon brush and Barnes CR-10 copper fouling eraser I don't prefer copper (unless you gents recommend it) because the cr-10 eats the brush also. I shoot 5 rounds and cool and clean the rifle before I shoot another group.. Is this to much? not enough? any advice is appreciated

 

[Timber338]

I basically follow Jim Borden's advice, below is a link to the article he has up on his website. I use Butch's Bore Shine followed by a light coating of Kroil. Make sure to read all of these instructions/advice such as why not to over-wet the bore with oil as well as why to never leave high-ammonia cleaners in a SS barrel. Because of this I avoid CR-10.

https://bordenrifles.com/wp-content/uploads/2015/12/clean_edited_april2010.pdf

There was a time when I was cleaning every 5 rounds (when my barrel was new), mostly because I did not trust that the bore was clean and I wanted to eliminate a dirty bore as a source for inaccurate shots. I quickly learned that my barrel would shoot 1/4 MOA past 20 shots. I have never tried to figure out the point where I lose accuracy. It's a hunting rifle, and my goal is to characterize performance on a cold bore that has been fouled with 1-2 rounds.

Any time I shoot the rifle I always finish by cleaning the bore and then shooting a fouling round, so that the next time I get out to shoot my first cold-bore shot is the same whether I am hunting or shooting at targets.

 

[Timber338]

Did you mean COAL of 3.915"?

Haha. Yes, good catch. Typo of course. 3.915" COAL with the 300 Berger EH.

 

[338RUML]

Ordered a few new brushes and some butch's bore polish today from midway I think I will switch to cleaning with it and using cr 10 every 30-40 shots to remove copper. If it would quit snowing I may be able to go shoot in the morning! thanks for the feed back timber.

 

[D.Camilleri]

I got tired of chasing groups, went to see my local gunsmith that installed my Broughton barrel and had him take a look with the bore scope. Long story short, my barrel had a lot of wear and I don't have much patience. I ordered a new barrel, a Bartlein 5c with a 10 twist and through a pure miracle, I have my gun back after 3 days with a new barrel, blueprinted action, muscle brake, wyatt's extended magazine box and I am waiting for my devcon to finish drying on my new bedding job.

I loaded up some Berger 300 gr OTM's with 90 gr of H1000 and seated to 3.800 which is about .090 off the lands. I also loaded some Bergers with 101 grs of RL33 also seated to 3.800. I also loaded some 300 gr accubonds with 101 grs of RL33 at 3.675 oal, which is about .040 off the lands.

 

[Timber338]

I think you made a smart choice going with a new barrel, I would have done the same thing. Life's too short to chase your tail with a barrel that doesn't shoot.

 

[338RUML]

Nice job!! Tell me,, what needs to be done for the Wyatt extended mag to be installed? please and thank you awesome turn around time! If you don't mind me asking how much did the whole switcharoo cost? I'm thinking about rebarreleing but I keep winding up with roughly 1100 dollar estimate I can't get myself to do it right now for that price haha

 

[D.Camilleri]

Sorry to say it but 1100.00 is pretty close for everything I had done. Just installing the Wyatt's box is about 125.00 and it requires machining the bottom of the action, tapering the inside of the bottom metal and modifying the floor plate spring. I might have been able to correct some of my issues if I would have inspected a little deeper. My picatinny rail was moving, but I couldn't see it until the rail was removed which showed two shiny spots. Then the gunsmith found several of the rail screws were bent. I still have my old barrel and I might consider cutting off an inch from the breech and rechambering to see how much it cleans up the rifling.