I'm assuming that any capacity gain in an improved cartridge is going to be toward the top of the case. That being said, would I be defeating my purpose by using longer bullets that protrude into the case a ways or can I still take advantage of the extra horsepower and push the heavier bullets faster?
Improved Cartridge Question
- Thread starter J300UM
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Greg Nolan
Handloader
- Nov 25, 2004
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J300UM
Now there's a catch 22. :?
Good Hunting
Elkhunt :grin:
Now there's a catch 22. :?
Good Hunting
Elkhunt :grin:
- Oct 30, 2004
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Usually 100-150 fps gain.
rick smith
Handloader
- Apr 6, 2005
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The improving straightens some of the taper out of the case as well as move the shoulder forward and change the angle. So you do have an increase of capacity. Haven't measured the increase. I have a 280 Rem and a 280AI. I shoot a 150gr NBT in the 280 but don't have the velocity available. In the 280AI I am pushing a 160gr to right at 3000fps. If you need more than that, go to a larger case.Rick.
It depends on what cartidge you are going to improve. example: 308 win has a 20 degree shoulder and a pretty minimum taper on the case where as the 30-06 has a 17.5 degree shoulder and a large amount of body taper. You will get much more gain out of improving the 30-06 than the 308 since improving cosists of minimum body taper and (generally) a 40 degree shoulder. The WSM's, and RUM's don't gain much from improving due to the 35 and 30 degree shoulders respectively and minimum body taper. However, the RUM's do get improved, and the gain is there. If you are seeking the ultimate power and want something a little exotic and don't mind fireforming cases, then go for it. However, Fireforming is barrel wear, and most hotrod cartidges have a finite amount of rounds that can be fired accurately through them. With the wealth of factory cartridges available, I'd consider bumping up a case size to get away from fireforming.
What cartidge are you thinking of improving???
Also, if you are seeking the best performance at long range, then you should be shooting the heaviest pill your rifle can handle. So the short answer is yes, it is worth gaining case capacity and shooting a heavier bullet within reason. But, if you get too out of hand, you will loose too much velocity to justify the increase in weight. If you going to have the money spent on rechambering and such, maybe think about simply having your throat lengthend and your magazine changed to allow you to seat bullets just down to the shoulder. I am planning a 260 project (in a couple years
) with a long action to allow me to seat 140 grain pills on top the case. Looking at any bench rest shooter, they are generally not using the biggest fastest gun, but they are always utilizing all of their case capacity by seating bullets out very far touching the lands and not sticking the bullet beyond the shoulder. Oh, and many if not most are using cartidges that have improved charactoristics (min taper, high taperd shoulders and usually short and fat rather than long and skinny).
All this of couse IMHO
nuff said out of my pie hole for a while
What cartidge are you thinking of improving???
Also, if you are seeking the best performance at long range, then you should be shooting the heaviest pill your rifle can handle. So the short answer is yes, it is worth gaining case capacity and shooting a heavier bullet within reason. But, if you get too out of hand, you will loose too much velocity to justify the increase in weight. If you going to have the money spent on rechambering and such, maybe think about simply having your throat lengthend and your magazine changed to allow you to seat bullets just down to the shoulder. I am planning a 260 project (in a couple years
) with a long action to allow me to seat 140 grain pills on top the case. Looking at any bench rest shooter, they are generally not using the biggest fastest gun, but they are always utilizing all of their case capacity by seating bullets out very far touching the lands and not sticking the bullet beyond the shoulder. Oh, and many if not most are using cartidges that have improved charactoristics (min taper, high taperd shoulders and usually short and fat rather than long and skinny).All this of couse IMHO
nuff said out of my pie hole for a while
- Thread starter
- #7
Thanks for the replies guys! It is my 300 rum that is getting rechambered. My gunsmith conned me into it and now I'm starting to wonder if I made a mistake. I guess I've always liked being a little different. If I knew then what I know now, I would have probably rechambered to a 338 edge. I was shooting the 200gr AB before. I was told I should go to a 180gr to take full advantage of the extra capacity and still have exeptional k.o. power down range. What do ya'll think? Again, thanks. Your opinions are highly valued!
rick smith
Handloader
- Apr 6, 2005
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Depends on what you have that needs killing. If the 180gr AB won't get the job done, you need a larger caliber not 20grs more bullet weight.Rick.
the 300 RUM and the 300 RUM improved will work best at 200 + grain bullets. I shoot a 300 WSM and the 190 grain boat tail is the bigest I will use in that case ( I actually shoot mostly 180 accubonds). Ya have to consider percentages when thinking about the case capacity. 2 grains of powder in my wsm is a bigger deal than 2 grains in a RUM. If you are hunting at extreme ranges only then set your throat for the 240 SMK If you want to have a rifle that is capeable of performing exceptionally well at all ranges than have it set for a 200 grain AB.
Also, I've heard good things about fireforming w/ cream of wheat and pistol powder = no barrel wear.
your RUM will have no problem pushing the heaviest of pills as long as you set your throat back to handle them.
Good luck, Mark
Also, I've heard good things about fireforming w/ cream of wheat and pistol powder = no barrel wear.
your RUM will have no problem pushing the heaviest of pills as long as you set your throat back to handle them.
Good luck, Mark
