Retumbo, 7RM, 180 Berger hybrid

mrb1982

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Got a good load at 2880fps with 70gr H1000 in my 7RM Sendero 26 inch barrel. Curious if people are getting a little more juice than that with Retumbo or not? If so, is it worth the extra speed for a little savings on drift or just stick with the load where it is at? Would it be conceivable to get to 2950 with Retumbo.

If not, and let's say I wanted a little more juice, is it possible to have my chamber reamed to a 7mm/300 win mag without having to get a new barrel? I got lucky and got a good 1/2 MOA factory barrel so I think it would be worth keeping it. Curious what people are experiencing and what my possibilities are with my existing rifle. Thanks
 

Lefty7mmstw

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As to your velocity on the 7rem chambering with 180's, you are there as to speed... You will reach your pressure top rather soon if you aren't there already so why bother pushing.

As to a re-chamber.... Yes, you can punch it out to 7x300win or 7mm stw.... The stw will net you a bit more velocity but the brass is a bit more scarce and expensive lately. If you care about the brass issue I'd go 7x300...

Here's a thought; shoot the 7rem barrel out, then re-barrel with a bit bigger chambering. You are only 200 fps down from what I'm pushing 180 sierra's at out of my 7rum with a milder load of retumbo...
 

MudRunner2005

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Try 7828 SSC... I get good velocities with 168's out of my 7mmRM.

I even get right at 3K out of 180 Hybrids with my 7mmSTW with no pressure signs using 7828 SSC, as well.

Both rifles are 26" factory Remington barrels.
 

mrb1982

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Bottom line is it probably isn't going to make a lot of difference at this point.

You are right, pressure is about maxed out on this load. When I worked up the load, it wasn't much over the 70gr where the pressure signs because a little too much.

You know how it is though, you always want something bigger, right? hahaha I know a lot of guys getting 3000k with their 7 mag. That would be about perfect. I am pretty sure I can't get there with this one though.

Is it even possible, if I were theoretically interested in having an STW or 7/300, to have it chambered in my exhisting rifle without having to rebarrel? If so, what does the average smith charge for this sort of work?
 

MudRunner2005

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You could, but if it were mine, I wouldn't spend the money on that barrel... That barrel you currently have is a slow one (some are fast, some are slow...Nature of the beast). I think you would be better off to drop the coin on a nice hand-lapped and air-gauged aftermarket 26"-28" 1:9 twist barrel (Bartlein, Brux, Benchmark, Krieger, Lilja, etc...), and have it chambered in your caliber of choice.
 

barefooter56

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Bottom line is it probably isn't going to make a lot of difference at this point.

You are right, pressure is about maxed out on this load. When I worked up the load, it wasn't much over the 70gr where the pressure signs because a little too much.

You know how it is though, you always want something bigger, right? hahaha I know a lot of guys getting 3000k with their 7 mag. That would be about perfect. I am pretty sure I can't get there with this one though.

Is it even possible, if I were theoretically interested in having an STW or 7/300, to have it chambered in my exhisting rifle without having to rebarrel? If so, what does the average smith charge for this sort of work?
mrb1982,
You could drop down to our 168 grain 7MM bullets. CLASSIC HUNTER or VLD. With a little load testing 3000 fps should be attainable. If that what your rifle likes.
 

mrb1982

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I actually have a load with 168's that I worked up before I did my 180's. I never got to the point where I got to test them out long to see how they did. I do shoot the occasional elk and it would be nice to stick with the 180's for that purpose. A million choices hahaha I haven't had the chance to shoot these 180's out to 1000 yet, but at 685 my drops come in at 2880. I don't have a chronograph so I have to do it the old fashioned way. I work up a load. Then I go out to distance and see what it takes to match up my drops. Worked pretty good this fall. I will be interested when I test it at 1000 if it still gives me close to that for my drops.
 

barefooter56

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I actually have a load with 168's that I worked up before I did my 180's. I never got to the point where I got to test them out long to see how they did. I do shoot the occasional elk and it would be nice to stick with the 180's for that purpose. A million choices hahaha I haven't had the chance to shoot these 180's out to 1000 yet, but at 685 my drops come in at 2880. I don't have a chronograph so I have to do it the old fashioned way. I work up a load. Then I go out to distance and see what it takes to match up my drops. Worked pretty good this fall. I will be interested when I test it at 1000 if it still gives me close to that for my drops.
mrb1982,
Welllll lets get on the stick here and test those puppies out at range! lol ! You may be pleasantly surprised. If you are looking for a good chronograph . The Magneto Speed is a good one to get accurate velocity figures on. Very nice tool.
 

mrb1982

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I have no fear of the 168's being good at long range. Definitely no doubt there. Just like the thought of a little bigger pill. I have run the numbers on the 168's and in all honesty, probably run almost better than the 180's. Sure do like seeing that big ole 180 harpoon sticking out of that case though. It makes you feel powerful!!!!! lol
 

mrb1982

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barefooter56,

Out of curiousity, how many fps would I gain from what I am getting from my 180's right now if I went to the 168's, all other pressures and everything being equal? Is there kind of good "guesstimate" on how many fps faster the 168's run compared to the 180's? I have a load I worked up at one point, I need to go back in my notes and see what the charge was, it was either 71 or 71.5 grains of H1000 if I recall correctly but I would have to look at my notes.

Just trying to get a good realistic fps difference between the two so that when I plug them into my shooter app I get some realistic drop verifications.
 

mrb1982

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So let's say that is accurate, then if I pick up 50fps with some Retumbo instead of H1000, that puts me around 3050 with the 168's. The ballistics on that are actually pretty good. Think if is possible?
 

barefooter56

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barefooter56,

Out of curiousity, how many fps would I gain from what I am getting from my 180's right now if I went to the 168's, all other pressures and everything being equal? Is there kind of good "guesstimate" on how many fps faster the 168's run compared to the 180's? I have a load I worked up at one point, I need to go back in my notes and see what the charge was, it was either 71 or 71.5 grains of H1000 if I recall correctly but I would have to look at my notes.

Just trying to get a good realistic fps difference between the two so that when I plug them into my shooter app I get some realistic drop verifications.
mrb1982,
To many variables. Only testing will give you accurate information. Guessing? Not so much. lol !!
 

mrb1982

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I think maybe I will try some Retumbo with these 180 and see what happens. Be a cheap try since I just need some powder. I have already run seating depth tests with this bullet. So I just need to load up some charges and see what happens I think. My gun has notoriously shot better with max or over max loads so I think I can start a little under max load and work my way up and see what happ3ns.
 

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