help me to understand a custom rifle build (updated 11/18)

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Precision
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Re: help me to understand a custom rifle build

Post by Precision »

slowpoke wrote:those look like sectional densities not ballistic coeffefients.
check again.
They are G7 BC's. That is what should be used with pointy long distance bullets that have boat tail backs and as an average over velocities not figured at peak velocity like G1.

for G1 BC more appropriate for pistol and flat based rifle bullets, but for comparison.

6.5mm at 140 gr .593 & 607

7mm at 168 .628
.......at 180 .680

.30 cal at 168 .507 & .515
.........at 185 .543, .555 , .576
.........at 210 .621 & .625

So again the lightest 7mm is better than either the 6.5 or 30cal from the BC stand point.
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HTRN
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Re: help me to understand a custom rifle build

Post by HTRN »

You didn't compare the 215 hybrid tactical, nor the 230, both of which surpass the bc of the 7 mil offering. But thats not why its such a not great idea. Ballistic coefficient is not the end all, be all of 1k, otherwise, everybody would be shooting .338 Lapuas. You're assuming that the gun is going to like those bergers. What if it doesnt? 160 grain Matchkings? With 30 caliber, you're talking dozens of alternate possibilities.

As for barrel contour, note two major points, slightly less weight, ESPECIALLY AT THE AWKWARD END OF THE RIFLE, along with 2 more inchs of velocity boosting barrel length. That contour won't get you much over a palma, and considering the compromise nsture of the design in the first place. If it was 17lb bag rider light gun, I'd agree with you, but the, you would be using a stiffer ss action, a 400 dollar trigger, and nightforce, in a very different stock.
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Precision
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Re: help me to understand a custom rifle build

Post by Precision »

First off in case you don't know already, I appreciate the critique and the options.

I think I have seen the light regarding the palma contour, will probably go to the medium weight contour. The extra length will be awkward in the field, but the loss of weight will balance for that and the extra velocity will be awesome. So your idea makes lots of sense.

For the longest time I was dead set on 6.5 x 284, but I never really like the 140(ish) gr limit. I have considered the 30 cal class but in order to reach all the way out there 300 win is the ticket and I am not sure how easily 30-60 shots will be for a 160# guy to absorb without a flinch or shooter fatigue by the end of a course. At the 215 and up bullet weight I think that recoil penalty is going to be a limiting factor for me. http://bulletin.accurateshooter.com/201 ... -analysis/ a summation of my thought. There are other 7mm heavy high BC manufacturers, but you are correct, not as many as in .30. I still have MONTHS before anyone is cutting a chamber, but I do want to figure out the basics. Thank you for your knowledge in this arena.

6BR, 6xc or the like would be the way to go if I didn't want it to be a dual use gun. But, I want hunting capability as well as tack driver and I may well play some of the tactical / prone courses so it can't be a 22# gun for either of those, see the weight of the driver.

I have an email in to Russo. Those are some nice looking stocks. I like the laminate ones. Thanks for that tip too.
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HTRN
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Re: help me to understand a custom rifle build

Post by HTRN »

Keep in mind too, that this is going to be north of 12 lbs of rifle, so its going to be relatively soft shooting.
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HTRN
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Re: help me to understand a custom rifle build

Post by HTRN »

Precision wrote: I meant to put Predator / Tac action. I can't find tolerance numbers / differences between the two. I will look at some of the other you mentioned as well.
I dont know off hand what the bolt cleareance is on the tac action, but the predator action is something like .006, while a factory Remington 700 is .008 and up. The Borden I mentioned is .0015, and it has "borden bumps".
HTRN, I would tell you that you are an evil fucker, but you probably get that a lot ~ Netpackrat

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Precision
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Re: help me to understand a custom rifle build

Post by Precision »

HTRN wrote:
Precision wrote: I meant to put Predator / Tac action. I can't find tolerance numbers / differences between the two. I will look at some of the other you mentioned as well.
I dont know off hand what the bolt cleareance is on the tac action, but the predator action is something like .006, while a factory Remington 700 is .008 and up. The Borden I mentioned is .0015, and it has "borden bumps".
I spoke with Stiller. They said the only really difference between the two is the color. Black paint. Sigh. .004 to .006 on either Stiller action


My question on the Borden. How is that tightness going to deal with dust and grit of being in the field? I know the Borden bumps make it "better" but I don't understand what they are / do and why I care. I assume it is not just marketing hype. Illumination would be a good thing. I don't mind paying $3-400 more for the action. Cry once and all that, but I would like to understand why.
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BDK
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Re: help me to understand a custom rifle build

Post by BDK »

I had a Bartlein 5R put in my rifle. If I could have gotten it faster, I'd have gone w a Schneider. Really, at the better grades, I don't think it matters who makes the barrel.
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Darrell
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Re: help me to understand a custom rifle build

Post by Darrell »

I see Sarco still has some of the Dumoulin Mauser actions, now up to $350. They are .30-06 family, according to the blurb. Would those serve for such a rifle as y'all are talking about?

http://www.e-sarcoinc.com/dumoulin-mauser-action.aspx
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HTRN
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Re: help me to understand a custom rifle build

Post by HTRN »

Precision wrote:My question on the Borden. How is that tightness going to deal with dust and grit of being in the field? I know the Borden bumps make it "better" but I don't understand what they are / do and why I care. I assume it is not just marketing hype. Illumination would be a good thing. I don't mind paying $3-400 more for the action. Cry once and all that, but I would like to understand why.
Most tight actions have fluted bolts to give any grit someplace to go. A tighter bolt fit means less slop, therefore greater concentricity. Borden bumps are a patented design feature on borden actions (and i believe nesika bay used to use them) on the bolt just behind the lugs, causing even tighter lockup. Basically, its a short eliptical cross section, that brings bolt clearance to zero when the bolt is turned. Theres a bunch of photos and videos about it online that explains it better than I can, just Google it.
BDK wrote:I had a Bartlein 5R put in my rifle. If I could have gotten it faster, I'd have gone w a Schneider. Really, at the better grades, I don't think it matters who makes the barrel.
All the better barrel makers go through hot streaks, its just that right now, broughton is the current tight setup.
Darrell wrote:I see Sarco still has some of the Dumoulin Mauser actions, now up to $350. They are .30-06 family, according to the blurb. Would those serve for such a rifle as y'all are talking about?
No.
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First Shirt
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Re: help me to understand a custom rifle build

Post by First Shirt »

Long enough, but the bolt face is wrong? Or is it just not long enough?
But there ain't many troubles that a man caint fix, with seven hundred dollars and a thirty ought six."
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