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MGM Ironman long range: Bolt or gas gun? (rookie question)


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Ziebart is right about the Savage 22. I have a TR, with a very affordable scope on it. If my wife doesn't go you could shoot my rifle. They have "t times" about every 30 mins, and we would just have to take turns. No big deal, I'd still be there shooting the breeze anyway.

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I have a perception problem on my home front. Another upper does *not* equal buying "another gun."

However, another gun *does* equal "another gun." I'm not saying I endorse this interpretation, merely that I have to live with it.

With regards to the longer range shooting, I'm less inclined to reloading. I don't have any equipment and I am worried that buying equipment would lead to scope creep (as in project scope, not optics) and erode most (or all) savings of doing a Grendel variant upper compared to doing a net new 308 AR size gas gun in 6.5 Creedmoor with factory loads. I'm taking my time learning all the equipment that would be needed for reloading in order to explore this concern.

So, it's looking more like either 24" 6.5 Grendel upper or 22"/24" 6.5 Creedmoor new gun, either with Hornady factory ammo.

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Just to shed a little light on Grendel barrel lengths, Bill Alexander states that the Grendel loses 6fps on average per inch when going down from 28" to 20". And I sure as hell won't ever want a 28" barrel, and the 24fps the 24" has over a 20" isn't worth the 4 extra inches to me. So my distant future 6.5 Grendel upper plans have 20" as a max length because of the diminishing returns from going any longer. I believe Bill says 23fps average loss per inch going from 20" to 16" which is starting to be a significant loss for a longer range build. Just my .02

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Just to shed a little light on Grendel barrel lengths, Bill Alexander states that the Grendel loses 6fps on average per inch when going down from 28" to 20". And I sure as hell won't ever want a 28" barrel, and the 24fps the 24" has over a 20" isn't worth the 4 extra inches to me. So my distant future 6.5 Grendel upper plans have 20" as a max length because of the diminishing returns from going any longer. I believe Bill says 23fps average loss per inch going from 20" to 16" which is starting to be a significant loss for a longer range build. Just my .02

I went back to the Alexander Arms web pages and linked to this directly from their home page: http://alexanderarms.com/images/pdfs/grendel_ballistics.pdf

I looked at the stated muzzle velocities for the 123 grain Lapua Scenar from the 19.5" barrel and the 24" barrel.

19.5" --- 2565fps

24" --- 2620fps

Differences: 4.5" of barrel and 55fps. That's the smaller half of the range from 28 down to 20 inches of barrel length. That's 12.2fps. To have the stated average of 6fps per inch, the difference from 28 to 24 inches must be small. And that could very well be. I'm not voicing any skepticism, simply doing some arithmetic. Given the cartridge and barrel diameter, That doesn't sound odd.

Even at about 12fps per inch, the 20 or 22 inch lengths (from Black Hole, for example) seem very viable barrel lengths to be considered for the intended use.

You raised a good point, thanks. I think the story would be different for any of the 6mm/243 variants on the Grendel case. What I've read indicates that they still show more benefit from the extra length.

Edited by michael1778
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Interesting. Now I really wish I could find the article that has Bill quoted as saying 6fps per inch, seeing that it's very much at odds with their websites data. Its quite possible his numbers were somewhat optimistic that day, I do remember it giving me warm fuzzy feelings when I read it which is exactly what optimistic velocity numbers are supposed to do.

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Interesting. Now I really wish I could find the article that has Bill quoted as saying 6fps per inch, seeing that it's very much at odds with their websites data. Its quite possible his numbers were somewhat optimistic that day, I do remember it giving me warm fuzzy feelings when I read it which is exactly what optimistic velocity numbers are supposed to do.

I think that the Velocity vs barrel length plot leans over and gets very flat looking somewhere approaching 24" and on out to 28". Then everything is consistent.

6.5 Creedmoor would solve all these problems, except the initial capital cost concern.

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I'm in the same boat, minus the Ironman aspirations (not yet anyhow), I wanna goof around in some DMR matches and I also don't really want to start reloading for it because like everything else I want to dabble in, reloading will turn into a full on obsession/second job for me. I'm going with a Grendel upper instead of 6.5CM for now for several reasons: I have a lower with a trigger and stock I'm comfortable with, I promised the wife after I had my 3 gun arsenal assembled I wouldn't buy any guns for awhile (remember, an upper is technically not a gun!), and I can assemble the upper one piece at a time so when I'm finally finished I won't even remember what it cost, so I can pretend there is no initial investment. I do second guess myself at least once a month when I see that factory Grendel and Creedmoor ammo prices aren't that different, but then I look at AR10 platform prices and I'm back to the Grendel. I would still like a 6.5CM rifle someday, just not any day soon.

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I don't know a lot about MGM but if you are only going out to 300 why need more then a 223? just asking.

I'm not sure where 300 entered into this. My understanding of MGM Ironman long range targets is that they are in the 700-900 yard range. That is the design driver for this.

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Hey Gose, in long range matches you get NO spotter. It's just you, your gun, and the good Lord.

But we're not talking long range matches here. We're talking about three bonus targets at a 3-gun match where you are allowed spotters ;)

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At Ironman the ranges for the bonus targets are generally 500, 700 and 900 yards. You can shoot all the ammo at them that you want, until you time out. And I agree with Stlhead, just go shoot the match, borrow a long distance gun the first year and get a feel for the match before you build a gun specifically for that match.

Doug

Edited by Doug H.
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At Ironman the ranges for the bonus targets are generally 500, 700 and 900 yards. You can shoot all the ammo at them that you want, until you time out. And I agree with Stlhead, just go shoot the match, borrow a long distance gun the first year and get a feel for the match before you build a gun specifically for that match.

Doug

Thank you. I do appreciate the advice.

About how many long range targets are there at Ironman?

Soonest that I could possibly go would be next year, regardless.

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At Ironman the ranges for the bonus targets are generally 500, 700 and 900 yards. You can shoot all the ammo at them that you want, until you time out. And I agree with Stlhead, just go shoot the match, borrow a long distance gun the first year and get a feel for the match before you build a gun specifically for that match.

Doug

Thank you. I do appreciate the advice.

About how many long range targets are there at Ironman?

Soonest that I could possibly go would be next year, regardless.

Usually 3 at around 500, one at 700 and one at 900. I think that last time I shot it you could score a total of 3 hits at each distance for a total of 9 bonus hits. I didn't shoot Ironman last year so YMMV. Stlhead shoots it every year and could give you a heads up on how it is run now.

Doug

Doug

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Yes, I'm rethikning this idea. I would get more return from improving my skills and getting my Open kit running in top form.

We will see. You and I might still want to have a "6mm" project for ourselves. :-)

I very much appreciate all the input in this thread. I look forward to reading any others that come along.

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At Ironman the ranges for the bonus targets are generally 500, 700 and 900 yards. You can shoot all the ammo at them that you want, until you time out. And I agree with Stlhead, just go shoot the match, borrow a long distance gun the first year and get a feel for the match before you build a gun specifically for that match.

Doug

Thank you. I do appreciate the advice.

About how many long range targets are there at Ironman?

Soonest that I could possibly go would be next year, regardless.

Usually 3 at around 500, one at 700 and one at 900. I think that last time I shot it you could score a total of 3 hits at each distance for a total of 9 bonus hits. I didn't shoot Ironman last year so YMMV. Stlhead shoots it every year and could give you a heads up on how it is run now.

Doug

Last time I shot it, I believe it was 5 hits worth 10s each / target, but it's been a while.

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  • 1 month later...

Most of the people I saw shoot the bonus targets at my first ironman last year used about as much time as they gained.

I am concerned that I would land in that category.

I'd rather engage targets and hit them for no gain than pussy out and not shoot them at all. To me it's about shooting and I go to matches to shoot targets not pass them up.

Doug

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Most of the people I saw shoot the bonus targets at my first ironman last year used about as much time as they gained.

I am concerned that I would land in that category.

I'd rather engage targets and hit them for no gain than pussy out and not shoot them at all. To me it's about shooting and I go to matches to shoot targets not pass them up.

Doug

Doug, you're killing me. That was very funny. I do see your point. I've got time to consider how to approach this match. Which division is actually the current issue on my mind.

I like carrying all of my stuff on my back, so...... :devil:

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I am not saying to not shoot them if you have the rifle or access to one, but I don't think I would revolve my preparation for the match around them. I went one for one on stage 4 on them and gained time. But I had access to a great rifle. If I had to travel a long ways for the match especially by flying I don't know if I would worry about them unless I could borrow a rifle.

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