New to the 300 Win Mag

[Ksmirk]

Evening folks, like the title I'm new to the 300WM and while I'm not new to reloading I think I'm having a problem as this round hold close to twice the powder I'm used to loading and feeling a touch reluctant so I wanted to just ask and hope that some of you folks have some good direction to point me or just tell me to grow a set lol

I know that the go to for the 215gr Berger is H1000 but I have close to 7# Retumbo I'd like to burn up and after this past weekend I don't think it will take long! what I have done is taken a SAMMI chamber and ran a throating reamer to where I could seat the bullets at 3.740" COAL to the lands give or take for bullet tip but an Ogive length of 2.935" is what I was loading. This rifle is a single shot by the way. I went off the book loadings and where Hodgdon says 81.0gr is compressed I still have a mess of room which I expected being I'm seating the bullets out to gain more powder space but where it starts to concern me is that I loaded up to 81.5gr thinking I may hit pressure I never got there! velocity is right at 3065fps SD's are not too bad but could be better I just don't know about going further or if I even need too?

I guess I'm just concerned as I've never dealt with a big boomer before and I can't really find a mess of info on Retumbo and long loaded rounds.... plus the amount of powder sorta worries me. So if any of you fella's have some advice to pass on I'd appreciate it greatly! Thanks in advance. Later,

Kirk

 

[joshb]

Tag

 

[pslater]

Evening folks, like the title I'm new to the 300WM and while I'm not new to reloading I think I'm having a problem as this round hold close to twice the powder I'm used to loading and feeling a touch reluctant so I wanted to just ask and hope that some of you folks have some good direction to point me or just tell me to grow a set lol

I know that the go to for the 215gr Berger is H1000 but I have close to 7# Retumbo I'd like to burn up and after this past weekend I don't think it will take long! what I have done is taken a SAMMI chamber and ran a throating reamer to where I could seat the bullets at 3.740" COAL to the lands give or take for bullet tip but an Ogive length of 2.935" is what I was loading. This rifle is a single shot by the way. I went off the book loadings and where Hodgdon says 81.0gr is compressed I still have a mess of room which I expected being I'm seating the bullets out to gain more powder space but where it starts to concern me is that I loaded up to 81.5gr thinking I may hit pressure I never got there! velocity is right at 3065fps SD's are not too bad but could be better I just don't know about going further or if I even need too?

I guess I'm just concerned as I've never dealt with a big boomer before and I can't really find a mess of info on Retumbo and long loaded rounds.... plus the amount of powder sorta worries me. So if any of you fella's have some advice to pass on I'd appreciate it greatly! Thanks in advance. Later,

Kirk

Kirk,

Using the Quick Load program data and your load parameters (throated SAAMI chamber, 81.5 gr. Retumbo, 215 Berger #30423, OAL 3.74) I get the following data:

Load compression: 104.2%
Muzzle Velocity with a 28" barrel: 2905
Shank (bullet bearing surface in neck) seating depth: .222
Maximum Chamber Pressure: 53,781 (this is a 64,000 psi chamber)

You will pick up approximately 85 fps with H1000 but the pressure goes to 64,000 psi. Most people seem to work with the shank depth at one caliber (ie. .308) but the single shot nature of your rifle may allow you to get away with less.

Please verify this data with others who have experience and/or have Quick Load. I hope this helps.

 

[Ksmirk]

pslater now I'm really confused lol we used my brothers magneto speed chronograph so I guess I need to verify with my CED. I do know the 81.5gr powder charge you can still rattle the powder around so I'm going to say this isn't a compressed load but it is good to see that I'm still away from the 64K pressure! I appreciate the info but I don't know anyone else who has QL software.

I guess with this being my first belted mag I'm just being way on the cautious side as any of the other rounds I shoot I just run up until I see a pressure sign and back off a touch. I've posted on a couple other forums I'm members of that they shoot the bigger rounds so hoping I get some info on their ends. I just feel that that velocity is rather fast but I have seen a couple rifles that were just odd balls! had a 284 Win I built that would flat out launch the 162's enough that my buddies with 7RM's bought a chronograph just to verify what mine was reading lol. Again thanks for running that thru QL, I appreciate your time. Later,

Kirk

 

[Wingnut00]

At that length of cartridge you are very close to the MRK248 MOD1 chambering which is the military's designation for their .300's throated for the 220 matchking. I have a 248 mod1 and although I never shot much retumbo through it I have no doubt it would work well. In my gun I run 230 hybrids in front of h-1000 at a length of 3.775 and when using the old blue bag Winchester brass my sweetheart load was cruising 2960 so I have no doubt that your 215's are flying like you say they are. Look up the MRK248 MOD 1. Lots of good info.

 

[x_wolf]

Ksmirk,
have you checked the capacity of your brass? There are HUGE differences between brands, even in production of one make - for example the Norma makes two sorts of 300WM, lighter and heavier, with very different internal capacity.
My go-to load in 300WM was HDY A-Max 208 with approx. 81,0gr. of H-1000. The old Sendero barrel is gone, now I have new 28" Bergara barrel and want try the 215 Hybrid with H-1000.