G
Guest
Guest
Has anyone tried cutting 300 Ultra Mag brass down to 2.500" and then necking to 7mm?? Should be nearly identical to the 7mm Dakota ballistically.
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7ultra
Well-Known Member
I think that basically is what the 7mm Dakota is. The only difference in case would be that the base of the 300 RUM is .550 compared to the Dakota's .544 and the rim diameter(RUM) is .532 compared to .544. Other than that the two would be so close, I would just save all the trouble/money and buy the 7mm Dakota. If that's the performance level that your looking for.
7ultra
Well-Known Member
Oh forgot to mention, the shoulders and tapers of the two cases are marginally different, but because they are both based off of the 404 style case, the differences would be purely academic.
G
Guest
Guest
The reason I posted this question is because I've heard bad things about Dakota brass. Like the brass being undersized causing shooters to get excessive amounts of expansion. What I want is something that will run with the 7mm STW but without the belt and long case. Currently have a winchester laredo in 7mm stw that I'm rebarreling because 162 gr a-max will not fit in the mag when seated to touch the rifling. C.O.L. over 3.75"
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rdm
It's true in my experience that the 7mm Dakota brass is small. I can't remember right now but I think the brass expands about .015 in headspace on its first firing. However, I get quite a few firings from it...maybe 10.
Also, in various rifles chambered in the 7 Dakota, with the 176 grain Cauterucio, I have gotten between 3130 and 3250 fps with a 32 inch barrel. Your mileage may vary.
It's true in my experience that the 7mm Dakota brass is small. I can't remember right now but I think the brass expands about .015 in headspace on its first firing. However, I get quite a few firings from it...maybe 10.
Also, in various rifles chambered in the 7 Dakota, with the 176 grain Cauterucio, I have gotten between 3130 and 3250 fps with a 32 inch barrel. Your mileage may vary.
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I don't think you could use the RUM brass in a Dakota chamber.
G
Guest
Guest
I guess I will go with 7mm rem mag. But man I sure would like to get rid of that belt and get that extra 200 fps. Just curious, what kind of groups were you getting with the 7mm Dakota. The barrel I'm gettting is a 28" Krieger with 9" twist.
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most groups are 5 shots in 1/2 inch at 100
This is great, I have been thinking about doing the exact same thing as an alternative to a 7 MM SAUM/WSM/Ultra Mag. Take a 7MM/300 RUM case and shorten it just enough to get a long seated 162 AMAX/168 Berger in the magazine well of a REM 700 LA.
I just did not want to have to have custom dies made.
So would it be possible to have a 7MM Dakota chamber cut, use 7MM Dakota dies, and 7MM/300 RUM brass?
I have 250 of those Federal 300 RUM brass that I would be willing to cut back and size to 7MM Dakota.
I also have a brand new REM 700 BDL in 7MM RUM waiting for a decision on what to chamber it to. If this will would work I have the answer.
Doug
[ 05-05-2004: Message edited by: dwm ]
I just did not want to have to have custom dies made.
So would it be possible to have a 7MM Dakota chamber cut, use 7MM Dakota dies, and 7MM/300 RUM brass?
I have 250 of those Federal 300 RUM brass that I would be willing to cut back and size to 7MM Dakota.
I also have a brand new REM 700 BDL in 7MM RUM waiting for a decision on what to chamber it to. If this will would work I have the answer.
Doug
[ 05-05-2004: Message edited by: dwm ]
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I now use a Redding full length bushing die and set the shoulder back about only .002.
Since going to this die system, I have not had to trim lengths after 5 firings so far.
Since going to this die system, I have not had to trim lengths after 5 firings so far.
Brent
Well-Known Member
Len,
I'm on the 9th loading with the Lapua brass, no anneal yet. After forming with Cream of Wheat I trimmed them all to 2.695 to clean them all up .005 or so, most of them were just under or right at 2.700 after forming. Chamber length for mine is .005 over the initial brass length, which ends up being 2.725. My brass has grown very slowly up to 2.715 and stabilized there, doesn't appear I'll need to ever trim them really. Maybe that will change when I anneal them and they'll grow a bit again... Mine only get bumped back a thou or so too. I do not miss the trim job.
A lot of it is probably due to the die not sizing the diameter down excessively as well.
I'm on the 9th loading with the Lapua brass, no anneal yet. After forming with Cream of Wheat I trimmed them all to 2.695 to clean them all up .005 or so, most of them were just under or right at 2.700 after forming. Chamber length for mine is .005 over the initial brass length, which ends up being 2.725. My brass has grown very slowly up to 2.715 and stabilized there, doesn't appear I'll need to ever trim them really. Maybe that will change when I anneal them and they'll grow a bit again... Mine only get bumped back a thou or so too. I do not miss the trim job.
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Brent
Do you think Malt-o-Meal would work almost as well?
Seriously, will you describe your method, please.
Do you think Malt-o-Meal would work almost as well?
Seriously, will you describe your method, please.
chris matthews
Well-Known Member
For what it's worth:
According to Grayback's Wildcat's (he sells fireformed wildcat brass)in Oregon, fireforming with cream of wheat, etc. is extremely hard on your barrel. Claims he has done extensive testing on it.
Could be he was blowing smoke up my *** to sell me brass. Could be he is right.
I have never used the filler method as I have only one Ackley rifle and I fireform with full loads. I'll leave it up for you all to decide.
According to Grayback's Wildcat's (he sells fireformed wildcat brass)in Oregon, fireforming with cream of wheat, etc. is extremely hard on your barrel. Claims he has done extensive testing on it.
Could be he was blowing smoke up my *** to sell me brass. Could be he is right.
I have never used the filler method as I have only one Ackley rifle and I fireform with full loads. I'll leave it up for you all to decide.
