300 Mag version of 6BR-AI (BRA)!

[SHall]

I welcome anyone that wants to try this round. That is why I included the reamer prints. It is hard to tell how well a cartridge will really do if only a couple of people are testing it.
Alex, do you have a reamer to make dies if someone wants to use your version? Post your chamber reamer prints here if you want. If someone uses my reamer (print) they will need to fire form 3 300RSAUM rounds and send to Whidden. I use Wilson Straight line dies that have been reamed with my chamber reamer.

 

[Kurz]

Why people care so much about the case name I'll never understand.

Alex,

I'm not sure that these references are as much about concern for the cartridge name as they are about having some fun with Sam. At least that's the emphasis I placed on my response, having a little fun. I could care less what anybody thinks the name of a particular cartridge should be.

My thinking and that of most others is directed at exactly what I wrote, the importance of refining cartridges and loads to achieve better performance and accuracy, no matter how insignificant those changes might be or may seem. The downside of sharing this information with the general public is the criticism from those less concerned with improving anything but accepting what exists. It has always been the folks who ask the questions and look for answers that move the rest of forward.

I'm grateful that you and Sam have put your own time and money into projects such as this. It save some of us the efforts.

 

[Alex Wheeler]

Yes, Sam I do have the resizer reamers. But if a guy was just going to do one for himself, then sending cases out like you did is much cheaper. The easiest/cheapest way may be to rent a Sherman 300 saum MAX. Its a little big at the base, but time would tell if the cases last or not. He would also have die sets in stock Id think.

 

[kev77]

I welcome anyone that wants to try this round. That is why I included the reamer prints. It is hard to tell how well a cartridge will really do if only a couple of people are testing it.
Alex, do you have a reamer to make dies if someone wants to use your version? Post your chamber reamer prints here if you want. If someone uses my reamer (print) they will need to fire form 3 300RSAUM rounds and send to Whidden. I use Wilson Straight line dies that have been reamed with my chamber reamer.

Thanks very much

 

[kev77]

Thanks everybody for posting their comments. I find this cartridge extremely interesting as I shoot the 7saum and 300wsm in fclass. The 300saum imp looks well suited for the 200x,210vld,215bergers. I would imagine it would shoot extremely well with h4350. What charge weights and barrel length are you guys currently using and what is your accuracy speed node with the bullet you're using . I believe this might be a very viable option do the quality of 300 WSM brass availability.

 

[SHall]

I use H4350. I am not sure if we are suppose to have charges on here. Most barrels I am shooting around 2830-2850fps with 204-207g VT. Same as a WSM with a few grains less powder and no pressure signs at all. I have a 5R barrel that shoot a tad over 2900fps with the same load with no pressure, the canted lands in some barrels will produce more velosity. I adjusted it back down to 2850fps that seems to be the accuracy node. All my barrels are 28 inches.
I think?? Alex likes R-23. I wonder how R-22 will do. A relative widower gave me a few 8 pounders of it a few years ago.

 

[kev77]

28" barrel at 2830ish to 2900fps is very respectable with h4350 and 200gr bullets.

 

[dkhunt14]

I use H4350. I am not sure if we are suppose to have charges on here. Most barrels I am shooting around 2830-2850fps with 204-207g VT. Same as a WSM with a few grains less powder and no pressure signs at all. I have a 5R barrel that shoot a tad over 2900fps with the same load with no pressure, the canted lands in some barrels will produce more velosity. I adjusted it back down to 2850fps that seems to be the accuracy node. All my barrels are 28 inches.
I think?? Alex likes R-23. I wonder how R-22 will do. A relative widower gave me a few 8 pounders of it a few years ago.

I agree with the canted lands part. I had a few in 6mm and 30 that were faster. I also thought they cleaned up a little faster. Matt

 

[Alex Wheeler]

I think @tom is ran the 215 around 2920 in 30"

 

[Kurz]

I use H4350. I am not sure if we are suppose to have charges on here. Most barrels I am shooting around 2830-2850fps with 204-207g VT. Same as a WSM with a few grains less powder and no pressure signs at all. I have a 5R barrel that shoot a tad over 2900fps with the same load with no pressure, the canted lands in some barrels will produce more velosity. I adjusted it back down to 2850fps that seems to be the accuracy node. All my barrels are 28 inches.
I think?? Alex likes R-23. I wonder how R-22 will do. A relative widower gave me a few 8 pounders of it a few years ago.

You can list charges but based on the reaction recently from a brass manufacturer, there are folks out here supplying charge information which is higher than acceptable. I blame this on a very few folks who lack the intelligence to actually shoot the loads they support in writing. The rest of us have been doing this long enough where we know the limits and respect the data supplied to us by the powder and bullet manufacturers. There have been and always will be variables from manufactured components, especially powder. So check everything before you pull the trigger.

I gave up on H-4350 when they first shorted us maybe 10 or so years ago. I am not able to stockpile cases of 8-lb jugs for all the different powders I use. So when a powder runs out in the supply chain I find another powder to use instead. This has worked for 4350 and Varget as well. I think I have 1-8lb jug of 4350 but it has a layer of dust on the top.

Re-22 has, in the past, showed us some substantial differences in lots and burn rates. If you have a large number of 8-lb jugs with the same lot number, you might as well try working up loads with it as it would be a shame to waste it. I switched to Re25/26 and never found a reason to change other than to run some more tests as other powders became available. Both powders work for me in both cartridges using heavier Match bullets. The 7mm RSAUM is usually loaded with 180 gr. Berger Match Hybrid. The 300 WSM uses the 200-20x or the 215 Berger Hybrid Target. The most noticeable difference occurs when I work on some of the solid Match bullets. I can't seem to get a hold of any of the Vapor Trail bullets so I am remiss in working up any load to compare. My barrels are all 30" with a taper from Bartlein in the 5R configuration.

 

[tom]

I think @tom is ran the 215 around 2920 in 30"

The upper node was about 2940 if i recall correctly in my 9 twist yes, with rl 16. Never worked that bullet with another powder as it shot pretty well to get a baseline and tell me the platform is good.

Tom

 

[boiler_house7]

I think most people on here know who run on the top. When something sparks Sam halls interest and Alex and Tom are testing there’s sure enough possible merit in these combos and lord knows there ain’t a magical round I’ve tested several myself. Being a F class shooter the ole faithful .284 is the foundation for sure. I’m knee deep in 7 rsaum Norma brass. I started testing the 20x in a straight 300 SAUM on 16 prolly a year ago. The results where very promising to say the least in the 2920 range on a 30”. The straight SAUM Really seems to be ideal capacity for the 20x, but it’s a throated and capacity wise a one horse round you might say. I’ve been playing with the 220’s in the wsm and seems to be showing promise on 23 on top node and nice on 16 lower node. I really appreciate these prints. I’m gonna get a 300 SAM-wheeler reamer coming for the adg brass an Norma both. I just gotta see what this holds for the 220’s. I don’t think the case will hold enough of 23 to make the top node at 2920ish, just a bit bulky, but 16 may without wrecking brass, just not sure. But the lower node 220’s was doing nice to in the wsm. This SAM-wheeler sure gotta help a bit on barrel heat over the wsm on these scalding strings I would think. The lot of 220’s I have has .020 less bearing surface than the 215’s so that can’t hurt. Where blessed with several bullets in this caliber and I think it could be a easy tuning, honest round with the right combo. I will be reporting on what I see for sure. Bill

 

[tom]

I don’t think the case will hold enough of 23 to make the top node at 2920ish,

I left off testing with my 207 and rl 23. My node when I pick it back up is 61.8 to 62.2...right at 2940. I took it higher, and although I didn't hit pressure signs, I didn't feel it would reach the next node. Just FYI.... I've become sidetracked on a different project lol.

Tom

Edit, I found the picture. I don't think I had the seating nailed down, but here is that initial ladder on 23. It wasn't compressed to cause any seating problems.

 

[kev77]

I left off testing with my 207 and rl 23. My node when I pick it back up is 61.8 to 62.2...right at 2940. I took it higher, and although I didn't hit pressure signs, I didn't feel it would reach the next node. Just FYI.... I've become sidetracked on a different project lol.

Tom

Edit, I found the picture. I don't think I had the seating nailed down, but here is that initial ladder on 23. It wasn't compressed to cause any seating problems.

View attachment 1175128

What distance was this , thanks

 

[kev77]

Sam and Tom, what freebore with what bullets are you guys using. Just trying to finalize my freebore length so I can order my reamer this week if possible. Thanks for your help. Kevin Lepine

 

[tom]

What distance was this , thanks

Been using my spot at 871 yards. Cuts about an hour off the round trip compared to either of my 1000 yard spots.

Bullets are a work in progress for me. I have a short freebore and long freebore to test many different weights/jacket lengths.

Tom

 

[SHall]

Sam and Tom, what freebore with what bullets are you guys using. Just trying to finalize my freebore length so I can order my reamer this week if possible. Thanks for your help. Kevin Lepine

My JGS reamer print is posted on my 1st post. It is a JGS with a .185fb. Even at that the 200 Hybrid and 200.20x are well away from the base of the neck. You could easy use a .160-.175fb for those. I had mine cut for the 207VT. Perfect for it. Samuel

 

[SHall]

For what it is worth. I had a straight 300RSAUM chambered for a 40 pound HG. It was a BRUX 1.35 straight, 28 inches, 1-10tw. I tried every good bullet I had in 200-207g. And exausted seating depth and powder charges. I was happy with the velosity, right up there with the WSM, low 2800’s. I have a load of Norma brass in 300RSAUM I bought a while back and wanted to see how a straight RSAUM would shoot without fire forming for the 300 Short Ackley. The chambering job was perfect, but for the life of me I could not get any load to remotely act like it was going to group at 500 yards! I’m talking 3 inch groups at best. I finially sent it Plainfield Precision and told Brian to ream it out with my 300 SAM reamer, slightly short chamber for a fire form barrel if it still wont shoot after re-chambering. He just set the barrel back a few thou. After fire forming a few rounds. I went back and tested with the same bullets, primers, powder, and even same brass. I was amazed immediately. Groups were near 1/2 the size. None were over 2 inches, most were in the 1.5-1.8 range. One was under one inch. It is hard for me to believe the AI made that much difference, but that is what happened. It may have been something else that sparked the barrel to life, I dont know? But I now consider it a competitive barrel and will try it at our next 1000 yard match. This barrel ran the 204’s up to 2920fps with no problem. DONT TRY MY LOAD DATA WITHOUT STARTING WELL BELOW! This BRUX barrel handles a lot of powder!

 

[Boatschool02]

My JGS reamer print is posted on my 1st post. It is a JGS with a .185fb. Even at that the 200 Hybrid and 200.20x are well away from the base of the neck. You could easy use a .160-.175fb for those. I had mine cut for the 207VT. Perfect for it. Samuel

Thanks for all this info.
-
With 0.075" between your freebore (+/- 200gr class) and Alex's 0.260" (215s, I'm guessing) I'm wondering:
- longest freebore someone ran with 20x?
-- (say, NLT 0.100 in the neck)
- or, shortest freebore run with 215s?
- or, accept they're not compatible & a throater is required?

 

[SHall]

Thanks for all this info.
-
With 0.075" between your freebore (+/- 200gr class) and Alex's 0.260" (215s, I'm guessing) I'm wondering:
- longest freebore someone ran with 20x?
-- (say, NLT 0.100 in the neck)
- or, shortest freebore run with 215s?
- or, accept they're not compatible & a throater is required?

Before giving you a fb number to order by, I would call the reamer manufacturer and tell them what bullets you intend to shoot. Or better yet, send a case and the bullets you intend to shoot to them to measure for fb.