Help determining velocities for different .338 bullet weights

[Good]

Hello, I'm having a tough time finding information on exactly what a .338 RUM will safely and reliably push different bullet weights. I thought it might be useful to consolidate all the information into one thread. Do any of you 338 RUM shooters have real actual data with Retumbo (Preferred) or similar powder that isn't very temp sensitive? I'm not looking for terminal performance or downrange ballistics, just specifically what the muzzle velocity range will be for certain weights of bullets at accuracy nodes, as fast as is safe, preferrably with Retumbo. Anyone have this kind of data for YOUR rifles? I'll update this first post with your information once it comes in. Thanks for your help.

Also, please note if pressure was not able to be reached due to bullet weight or whatever reason, so a different powder is best for certain bullet weights.

185g speed-

200g speed-

215g speed-

225g speed-

250g speed-

275g speed-

285g speed-

300g speed-

 

[Long Time Long Ranger]

I have enough data for a few books on this cartridge and it's mate the 338-300 RUM from when it was first introduced in 2001 when I was comparing it head to head with the 338-300 RUM I had been working with since 1998. I do not have time to go back and dig into boxes of data right now but can tell you the best powder for bullets of 225 grains and over is Retumbo. It will give the best pressure/velocity ratios. H-870 worked well with the 300 grain SMK when it was around. Max loads with the 300 grainers will run 92-93 grains with H-1000 and 94-95 grains of Retumbo in most rifles with fed 215 primers. Velocities depend on the barrel length and the individual barrels but will range from 2725-2925 fps safely depending on the barrel. Very little is gained from 26-30 inch barrels in all the testing I did with this one and the 338-300 RUM. I talk about both synonomously because they are the same thing performance wise and shoot the same loads. 15-20 fps per inch is the most you can expect and individual barrels can make more difference. I have seen shorter barrels outshoot longer ones and either cartridge outshoot the other just depends on the barrel.

With 185-200 grain bullets old winchester wmr was the best but they quit making it. RE-19 and IMR-4350 are very good with the lighter bullets. Powders in those burn rates give best performance. 7828 also does well.

With the 225 grain bullet the best load I have found is 101 grains Retumbo shooting 3350 fps out of my 26" barrel rifle. RE 25 and H-1000 also shoot well with all bullet weights but overall the best loads on average were with Retumbo.

 

[davewilson]

i have 2 338/300's. the big one i shoot the 285 hornady's and it just works well with H1000 powder so i never really experimented with anything else. my little one is a carry gun that i shoot the 225's and i like the Norma MRP powder. for me, it worked better than Retumbo with this gun. i can shoot them 3420 with a 28" barrel, but i use RWS brass!

 

[Good]

Well, I can't edit my first post so I'll just continue to update in this fashion until we can get all this info set up.

Thanks for the replys. I would like to try MRP but I can't get it within 150miles of me and shipping is way expensive so it's out of the question. I can get the Hodgden powders locally and I have 2lbs of Retumbo already so that's what I'm interested in. In other calibers I've tried the Alliant powders and didn't like them. I just keep going back to the H series.

This is really only a thread for the standard 338RUM and not the 338-300 (edge) or Lapua or anything else. I wished I would have named it correctly...

185g speed-

200g speed-

215g speed-

225g speed- 101g Retumbo 3350fps

250g speed-

275g speed-

285g speed-

300g speed-

 

[Long Time Long Ranger]

Since you want to work with Retumbo and it is the powder I have had best results with I will list some of those for you.

With the 300 SMK the best load I have found is 94.5 grains Retumbo with a fed 215. My 26" rem 700 shoots that load 2780 fps, 28" Pac-Nor=2825 fps, 30" Hart= 2880 fps.

The 285 Hornady I have only shot out of my 26" remington. 96 grains retumbo shoots 2865 fps.

With the 250's 98 grains retumbo shoots really well at 3140 fps out of my 26" remington. Out of the 28" pac-nor they averaged 3175 and the 30" Hart 3210 fps. These are max loads so if you try them work up in your rifle because different chambers and seating depths can drastically change pressures when you are working right at max.

Understand that I built many rifles and kept the fastest barrels in my collection. These are loads out of just three rifles. I can give you averages out of several when I tested the 338 RUM and 338-300 RUM head to head when the 338 RUM first came out. So like anything you read where a guy is getting 2925 fps with a 300 grainer which is way on the high side for the 338-300 and the 338 RUM there are just as many getting 2775 fps with the same load. It just depends on the individual barrel and chamber. So that is why in the first post I gave you a range of what you can expect and 99% of the rifles will fit in that range safely.

 

[highridge1]

It's great to compare others load data as a reference ,but just keep in mind that others data could be over max and too hot in your rifle. Everyones barrels are different along with, bore and chamber specs. What matters is what your rifle will shoot the best and safely. I really like 90.0 grs of RL 25 pushing a 300 gr SMK, I had a lower ES and better velocity than H1000 and retumbo. I have also had a big issue with lot to lot consistency with H1000 and retumbo. I have not had these troubles with RL25. I have had loads with H1000 that had to be changed up to 4 grs changing lots of powder. To me that is completely unacceptable.

 

[Long Time Long Ranger]

Good points. It looks like we are shooting about the same pressures as 94 grains of retumbo translates to about 90 grains of the faster RE-25. I have had some great loads with RE-25 also and the hodgdons does seem to vary quite a bit lot to lot. I recomend anybody buy an 8 pound keg so your not adjusting your loads so much. I try to work with the extreme powders as much as possible because of the temp variance.

 

[Good]

Since you want to work with Retumbo and it is the powder I have had best results with I will list some of those for you.

With the 300 SMK the best load I have found is 94.5 grains Retumbo with a fed 215. My 26" rem 700 shoots that load 2780 fps, 28" Pac-Nor=2825 fps, 30" Hart= 2880 fps.

The 285 Hornady I have only shot out of my 26" remington. 96 grains retumbo shoots 2865 fps.

With the 250's 98 grains retumbo shoots really well at 3140 fps out of my 26" remington. Out of the 28" pac-nor they averaged 3175 and the 30" Hart 3210 fps. These are max loads so if you try them work up in your rifle because different chambers and seating depths can drastically change pressures when you are working right at max.

Understand that I built many rifles and kept the fastest barrels in my collection. These are loads out of just three rifles. I can give you averages out of several when I tested the 338 RUM and 338-300 RUM head to head when the 338 RUM first came out. So like anything you read where a guy is getting 2925 fps with a 300 grainer which is way on the high side for the 338-300 and the 338 RUM there are just as many getting 2775 fps with the same load. It just depends on the individual barrel and chamber. So that is why in the first post I gave you a range of what you can expect and 99% of the rifles will fit in that range safely.

Thanks LTLR, that is exactly the kind of information I'm looking for, all consolidated into 1 thread. Absolutely perfect!

185g speed-

200g speed-

215g speed-

225g speed- 101g Retumbo 3350fps

250g speed- 98g Retumbo- 26" 3149, 28" 3175, 30" 3210

275g speed-

285g speed- 96g Retumbo- 26" 2865

300g speed- 94.5g Retumbo Fed215- 26" 2780, 28" 2825, 30" 2880

It's great to compare others load data as a reference ,but just keep in mind that others data could be over max and too hot in your rifle. Everyones barrels are different along with, bore and chamber specs. What matters is what your rifle will shoot the best and safely. I really like 90.0 grs of RL 25 pushing a 300 gr SMK, I had a lower ES and better velocity than H1000 and retumbo. I have also had a big issue with lot to lot consistency with H1000 and retumbo. I have not had these troubles with RL25. I have had loads with H1000 that had to be changed up to 4 grs changing lots of powder. To me that is completely unacceptable.

Yeah, this is just for reference and I'm just trying to get some real world numbers for apples to apples ballistic comparison, rather than relying on manufacturer "lawyer safe" numbers. It would be good also to do the same thing with "real world" numbers using other powders also, but Retumbo will be my powder unless I don't have favorable results.

I guess I must state as you guys already have, for those new to reloading, don't start with these loads as they may blow your face off! Start several grains lower and work your way up. Also, there's no telling precisely where YOUR accuracy nodes will be without working up so it's pointless to start here anyway. These numbers are just representative of what is possible and what people have found with their respective guns.

 

[GNERGY]

180 gr. Nosler BT 91gr. AA XMR 4350 gave me 3650 fps.

225 gr. Barnes TTSX 92gr. H4831SC gave me 3217 fps

250 gr. Berger Hybrid OTM Tactical 91.5gr. IMR 7828 SSC gave me 3160 fps.

250 gr. Berger Hybrid OTN Tactical 90.5gr. H 4831 SC gave me 3060 fps.

All loads are out of a 30 inch Broughton 1 in 9.3 twist 338 Ultra mag.
Those were my accurate loads, not necesarily the fastest for that bullet.

Tarey

 

[Dick Tinsley]

Hey Guys! Just run across this tread looking for info for the 338 ultra mag an 285gr A-Max bullets. I know this is a old tread, but mabey we can jump start it. The set up I'm using is a remington mod 700 stainless,28" Pac-Nor barrel, 1n10 twist. Been shooting 250 gr AccuBonds but they are hard to find now days. I've got some 285gr A-Max bullets comeing an was wondering if some of you had a good recipe for the 285's. I've got H-1000, Retumbo an RL-33(1pound). The H-1000 an Retumbo I've got plenty to load with as I load for two other calibers also! Any help will be appreciated!

DT