LRNut
Well-Known Member
Maybe he hit a clay pigeon once. The TOF at a mile is enough that you can't estimate the wind accurately, to say nothing of the accuracy required in the first place.
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New build, 7mm rem mag?
- Thread starter bowhunterjae
- Start date
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No. That's not what I said! But it is sub 1/4 MOA.
DirectDrive
Well-Known Member
Make sure that PTG has these in stock and you're not tied up in a Back Order situation.
I always check stock before ordering from them.
1:8 would be a good twist rate.
Do you want button rifling or cut rifling ?
Shilen is button and they have a good rep.
Bartlein is cut and will cost you a little more. Some insist on cut rifling.
Study the contours and the weights.
Bartlein 2B would be a good contour.
AG Composites Alpine Hunter is a good example of a "vertical grip".
Available in both fiberglas and carbon fiber.
I like BDL for a hunting rifle.
I don't want a mag hangin' down right in the spot where I oftentimes like to carry a rifle from.
The Triggertech tech triggers use a roller at the friction point which makes them very smooth.
Spend some time on a ballistics program. At what point does the heavier slower 180 start being better than the 160-168 with it's higher speed? At 600 and under, there is no use in using a 180 unless you are after elk. 160-168 out to 1200 carry the freight best. Using 180's, you will need at least .210-230 of throat, which also creates another issue with Mag box length, which the Wyatts mag box will fix handily.
I use 8.75,8.5, and 8.0 twists only when needed, otherwise, 9 twists fill the bill. I have an 11 Twist on a custom 27" Pac Nor three groove in 7 STW(zero freebore)where I shoot the 140 Nosler C/T at 3675 into dot size groups along with the 120g Barnes TTSX at 3875 fps. Huge deer have flopped at 550 yards in Kansas with the 140. HUGE Kansas bucks have flopped at 550 yards with the 140C/T at 3650!
Pick your choices in throat length, and twist rate based on your actual hunting circumstances, and do not build a 1600-yard load unless you are actually going to hunt/shoot that far, impact velocity on the animal is a HUGE consideration.
You will need a gunsmith who knows how to use a unitholder or has a reamer set up for 180s as the standard 7 Mag freebore is .110.
I use 8.75,8.5, and 8.0 twists only when needed, otherwise, 9 twists fill the bill. I have an 11 Twist on a custom 27" Pac Nor three groove in 7 STW(zero freebore)where I shoot the 140 Nosler C/T at 3675 into dot size groups along with the 120g Barnes TTSX at 3875 fps. Huge deer have flopped at 550 yards in Kansas with the 140. HUGE Kansas bucks have flopped at 550 yards with the 140C/T at 3650!
Pick your choices in throat length, and twist rate based on your actual hunting circumstances, and do not build a 1600-yard load unless you are actually going to hunt/shoot that far, impact velocity on the animal is a HUGE consideration.
You will need a gunsmith who knows how to use a unitholder or has a reamer set up for 180s as the standard 7 Mag freebore is .110.
Shortmag11
Well-Known Member
- Joined
- Apr 29, 2017
- Messages
- 584
Lots of good recommendations here!
The main reason for a vertical grip is that it allows your shooting hand to keep a "neutral" position (no twist in the wrist) and keeps your trigger finger in line with the bore so you can get a better "straight back" trigger pull.
Negative comb just means that the top of the stock (where your cheek rests) sits a bit higher at the back than it does in the front. That way, when the rifle recoils, the comb is moving away from your cheek, rather than smacking your cheek.
Wow that escalated quickly. As you can tell everyone has opinions and most of them are just that. The guy doesn't want a 7prc or a 280. He's said 180s are what he wants to shoot. Stop telling him he doesn't need 180s or he should ditch the 7mag cuz it has a belted cartridge and only "special" gunsmiths know how to cut those chambers. This is all hogwash.
OP, the 7mag is a fine choice. It's been doing it for decades as you know. 8T is perfect for 180s (8.4ish twist for 180s and below, 8 twist for 180s and up generally). I've seen a number of Shilens shoot lights out, run it with freebore if you wanna shoot 180s for best results but you don't need to like others claim. I have several SAAMI 7mags 24"-26" and they shoot 180s past 3000fps.
OP, the 7mag is a fine choice. It's been doing it for decades as you know. 8T is perfect for 180s (8.4ish twist for 180s and below, 8 twist for 180s and up generally). I've seen a number of Shilens shoot lights out, run it with freebore if you wanna shoot 180s for best results but you don't need to like others claim. I have several SAAMI 7mags 24"-26" and they shoot 180s past 3000fps.
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Buckys
Well-Known Member
John, I have been considering similar projects.
Perhaps the difference for mine might be that I would like to be able to shoot e.g., 140-180 grain bonded or cup-n-core projectiles as well as 1.35"~1.5" monos.
Still considering if 1:8" is faster than I need and hence might go with 1:8.7 or similar instead.
Precision hunter with flush mag gets it pretty tight. But totally get what you're saying.
I ordered the 1:8 on my current, in progress build because I wanted options, and the general consensus was it won't hurt you on lighter bullets 
As most of my shooting will be 160-168gr, and also want to try some lighter stuff, hope the consensus was right!
I'll know if I screwed up soon enough.
From what my ballistics calculator tells me, the 180 and above lose too much velocity to provide the terminal performance I'm looking for at 600yds from a 280AI.. 7 mag should take it out a bit farther.
Not a fan of the LR soft nose projectiles, I've seen the 80-100yd explosions with little internal damage. I like an AB or Mono.. just me.
As most of my shooting will be 160-168gr, and also want to try some lighter stuff, hope the consensus was right!
I'll know if I screwed up soon enough. From what my ballistics calculator tells me, the 180 and above lose too much velocity to provide the terminal performance I'm looking for at 600yds from a 280AI.. 7 mag should take it out a bit farther.
Not a fan of the LR soft nose projectiles, I've seen the 80-100yd explosions with little internal damage. I like an AB or Mono.. just me.
Wondering what kind of terminal performance you're losing out of a 180 at 600 yards? I guess I'm confused because you're talking about a 280 with 168s....but a 7mag will run the same numbers/or better as your 280 with 168s at any range but also do it with a 180 or maybe even a 190...are you comparing a 280 with 168s to 7mag with 180s? Rather confusing as the OP is building a 7RM to shoot 180s not a 280 to shoot 168s. Either way the 7mag loses nothing to a 280 with either bullet less than or beyond 600 yards. Basically the 7mag will outrun the 280 with any bullet at any range
As for steel playing...what's the difference? Again confusing. Why is it that only steel is what a 180 is good for? I think the OP would like some clarification on this point of view?
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Sorry if I wasn't clear.
I'll attempt to address the effects of twist rate and bullet weight in 7mm relating to terminal performance at longer distances.
708-280-7RM-7PRC-280Nosler are all effected in a similar manner to specific twist rates with specific bullet weights. Light bullets need slow twist, heavy bullets require faster twist.
Bullet weight determines how fast any rifle can push the bullet out of the barrel. Lighter bullets go faster than heavier bullets in the same caliber.
My calculator says, 180gr bullets drop below 2000fps (terminal performance) closer than the 160-168gr bullets based on how fast either can be pushed, using BCs common to each weight. I assume this is the same across ALL 7mm as it's basic physics. Gravity takes its toll.
In my rifle (280AI) I am looking for 2000fps+ at 600yds for hunting. I can not get there with a 180, but i can get there with 160-168. Yardage will differ with other variants of 7mms but it's the same principle with any rifle.
"What's the difference with steel".. HUGE. When playing with steel, it really doesn't matter how fast it is going when it contacts the steel.. who cares it just goes "ding". The super high BC 180, 190 or 210 have a wind advantage in that game.
In hunting impact velocity is critical, it's a balance of velocity and bullet weight. Bigger is not always better at longer ranges. Therefore twist rate selection becomes important to the distance you want to be able to make ethical kills.
As has been noted, running various bullets through a ballistic calculator can assist in selecting twist rates for a particular application.
I'll attempt to address the effects of twist rate and bullet weight in 7mm relating to terminal performance at longer distances.
708-280-7RM-7PRC-280Nosler are all effected in a similar manner to specific twist rates with specific bullet weights. Light bullets need slow twist, heavy bullets require faster twist.
Bullet weight determines how fast any rifle can push the bullet out of the barrel. Lighter bullets go faster than heavier bullets in the same caliber.
My calculator says, 180gr bullets drop below 2000fps (terminal performance) closer than the 160-168gr bullets based on how fast either can be pushed, using BCs common to each weight. I assume this is the same across ALL 7mm as it's basic physics. Gravity takes its toll.
In my rifle (280AI) I am looking for 2000fps+ at 600yds for hunting. I can not get there with a 180, but i can get there with 160-168. Yardage will differ with other variants of 7mms but it's the same principle with any rifle.
"What's the difference with steel".. HUGE. When playing with steel, it really doesn't matter how fast it is going when it contacts the steel.. who cares it just goes "ding". The super high BC 180, 190 or 210 have a wind advantage in that game.
In hunting impact velocity is critical, it's a balance of velocity and bullet weight. Bigger is not always better at longer ranges. Therefore twist rate selection becomes important to the distance you want to be able to make ethical kills.
As has been noted, running various bullets through a ballistic calculator can assist in selecting twist rates for a particular application.
I'm going to be the oddball. I like the REM 7mm mag. got some myself. They've always performed admirably. But, they have one big draw back. That stinking belt. Don't need them. They worked great on the long sloping .300 and .375 H&H cases. I will probably never get another one. In fact, I will probably never build or get a rifle with a belted case again. Lots of "magnum" size cases without that un-needed belt. But, to each his own. One guy told me that he owned over a dozen 7 mags. Told me, he just liked them. Couldn't argue with his logic.
