darrindlh
Well-Known Member
I am curious as to why the best of the west is using retumbo for there 7mm? I am no where near there caliber at all just wondering though? Does the 7mm burn slower than 338 win?
Darrin
Darrin
338 wim max effective range.
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MontanaRifleman
Well-Known Member
I think a lot of it has to do with the bore size vs the case capacity and length. Retumbo is a good powder for the 25-06, 7RM and RUMs but too slow for the 338 WM.
Limbic
Well-Known Member
That's good logic Montana and I never thought of it that way. Makes sence.
darrindlh
Well-Known Member
So I am correct in thinking that bigger the bore size faster I need the powder to burn? Is that correct or am I way off.
The max effective range would depend on what kind of bullet performance a hunter would want. A violent expanding, not consistent in passthrough or a harder consistent passthrough type bullet?
The softer bullets have the farther max range than harder bullets but shoulder shots can stop a soft bullet while the harder bullets will only do pencil holes beyond its distance..
The softer bullets have the farther max range than harder bullets but shoulder shots can stop a soft bullet while the harder bullets will only do pencil holes beyond its distance..
darrindlh
Well-Known Member
Right now I am loading up some barnes mrx bullets for when I get my 338. These seem to be violent expansion right? at least that is what they claim
Darrin
Darrin
MontanaRifleman
Well-Known Member
Based on my own experiences and what I've read and observed here, generally, the bigger the bore size vs the size and length of case, the faster the powder requirement. Construction, weight and velocity of bullet will also play a factor. i.e., If we look at the 300 RUM, Reumbo is a good bet for the 200-210 g bullets with velocities around 3150-3250. For the 180 bullets, H1000 might be a better choice with velocities of about 3400 and higher. With the GS 177, which gives better pressure/velocity ratios, RL17 might be a good bet for velocities of around 3550 give or take.
If you look at the 7WSM vs the 7RM with same weight bullets, the shape of the cases vs the bore size seems to definitely have an affect on powder choice with the 7RM having a longer and slightly larger capacity, liking slower powders better.
MontanaRifleman
Well-Known Member
I think what he means by violent expansion is highly frangible, explosive bullets like the Bergers. Which MRX's are you using? The 225 TTSX has a much better BC than the 225 MRX
darrindlh
Well-Known Member
I think that I get it. Eventhough the 338 caseing is the same length and width as the 7mm with the exception of the neck. B/c of the bigger bore diamater it likes faster burning powders i.e. rl19, rl 17 imr 4350 powders of that sort. correct?
MontanaRifleman
Well-Known Member
Yup, that's it.
darrindlh
Well-Known Member
Montana rifleman thank you so much for being patient with me. I really appreciate it
darrindlh
Well-Known Member
I was loading up some 225's. I am also going to get some ttsx for that reason. A higher ballistic coefficient. I am waiting for the bergers and Also thinking about the accubonds. What are you using and how are your groups?
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Yes, fragile vs tougher bullets
Berger VLDs are different than any other popular hunting bullets in one dominant way- the unique design that it penetrates upon entrance better than any competing hunting bullets.(delayed expansion for the first few inches) Which means this is the only fragile bullet to go right through the shoulder. And yet the vlds are not consistent for complete passthrough which is pretty much what all fragile bullets do.
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darrindlh
Well-Known Member
When do the bergers come out for the 338?
