I just reloaded some cartridges for 300 win mag with retumbo powder. I followed the hodgdon website recommendations for the load. 220 gr HPBT Sierra MatchKing is the projectile. Winchester large rifle magnum primers. I used a charge of 77 gr and had a couple primers blow out. I backed down to 76 gr but the primer still showed cratering. What should I try with this powder? Random info, I've heard that it acts different if it is a compressed load vs not compressed?
Hodgdon Retumbo 300 Win Mag
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Quicksilver338
Well-Known Member
What brass? What COAL? How close to the lands is it being jumped? Does the load feel compressed or close to it?
Every situation is different. I'd jump to 74.5 and work up from there. What velocities are you getting compared to the book?
Every situation is different. I'd jump to 74.5 and work up from there. What velocities are you getting compared to the book?
I'm new to reloading so i dont have a chronograph yet. It's being jumped 0.012in. Federal brass.
I guess I wondered if it was best to drop the load or hunt for a different powder.
It is close to being compressed, but it isn't.
MagnumManiac
Well-Known Member
I have several match chambers that will not tolerate a jump that close. They like a running start, I would start by seating deeper away from the rifling.
Blown primers are a dead giveaway of excessive pressure, I bet bolt lift was stiff or sticky too.
What COAL are you running?
To touch the lands in my rifle barrels, I need a COAL of 3.550". If yours is less than this, you have a short throated rifle IMHO.
Cheers.
Blown primers are a dead giveaway of excessive pressure, I bet bolt lift was stiff or sticky too.
What COAL are you running?
To touch the lands in my rifle barrels, I need a COAL of 3.550". If yours is less than this, you have a short throated rifle IMHO.
Cheers.
My COAL was 3.480 for this round. Which i suppose then i would need 3.492 to touch the lands. So what does it mean that I have a short throated rifle? How does it need to be treated versus a rifle that doesn't have a short throat?
MagnumManiac
Well-Known Member
Loading close raises pressure, loading away reduces pressure.
If you are happy running a few grains less powder and the accuracy is there, due to your higher pressure, you may be running at higher velocity with less powder.
I know this is true with my match chambers, I am at max a few grains under max in most books.
I run Retumbo too, but with 215's. I max out at 81.5gr. The throat on my rifle allows a little more powder, but this is MY MAX. Brass life suffers past that load.
Cheers
If you are happy running a few grains less powder and the accuracy is there, due to your higher pressure, you may be running at higher velocity with less powder.
I know this is true with my match chambers, I am at max a few grains under max in most books.
I run Retumbo too, but with 215's. I max out at 81.5gr. The throat on my rifle allows a little more powder, but this is MY MAX. Brass life suffers past that load.
Cheers
So would you recommend seating the bullet a little deeper? Like how much? And try a few grains less powder? Am I okay running magnum primers?
MagnumManiac
Well-Known Member
You can try the Berger/Litz seating depth test and see how it goes. I forget the distances they recommend, something like .040", .080", .100" and .120" from my poor memory.
I jump roughly .120" in my rifles.
Cheers
I jump roughly .120" in my rifles.
Cheers
Great, thanks for the help.
You've probably got a saami spec chamber which means it's got a short throat and better set up for 180 class bullets. If your running compressed now or close to it seating the bullet deeper will make things even more compressed, if you can get your hands on some H1000 give that a try or some other options are switch to lighter bullets or have it throated for the heavier bullets it your dead set on running them.
7, Retumbo is very touchy to charge increments. I've seen Federal brass pop primers on second firings in several calibers. Nosler, Norma and Lapua brass is the way to go. Remington brass is good also, but takes a lot more prep prior to loading. Good luck
DUSTY NOGGIN
Well-Known Member
WLRM primers , seem to be some of the hottest primers , i don't crimp mine, yet sometimes i wonder if a crimp would help with these primers. i wonder if the bullet release might be happening right before powder ignition, i did have a 300rum load that maxed out at grain over book start that was using WLRM primers and retumbo( but shot great !! )
id stay with the magnum primers , cause thats what it calls for , but if you tried a different brand ? , i switched to cci250
i like retumbo it works good, but i use the 8 lb bottle for the reason of variation from lot to lot . i found that when using 1 lb bottles you ended up tweaking the load every new bottle , due to it not shooting the same. since 1 bottle only equals about 75-100 rounds in the magnums its intended for , a new bottle is way too frequent . i end up using at least a 1/4 of that bottle getting it back to good . a 1 lb bottle in any slow magnum powder just doesn't make sense unless your trying a new powder or for a hunting gun that only gets shot once a year
id stay with the magnum primers , cause thats what it calls for , but if you tried a different brand ? , i switched to cci250
i like retumbo it works good, but i use the 8 lb bottle for the reason of variation from lot to lot . i found that when using 1 lb bottles you ended up tweaking the load every new bottle , due to it not shooting the same. since 1 bottle only equals about 75-100 rounds in the magnums its intended for , a new bottle is way too frequent . i end up using at least a 1/4 of that bottle getting it back to good . a 1 lb bottle in any slow magnum powder just doesn't make sense unless your trying a new powder or for a hunting gun that only gets shot once a year
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