Barrel twist rate for 20" 270.

[Mr. Zorg]

You asked smart guy...
Why don’t you tell us the cons for a bolt action?
I see two for a semi auto, and no others.
Or should we only let him know certain information?

Well instead of being absolutely asinine in plucking a quote completely out of context to coment on not-so-wise-guy, how about something constructive as I said before? It certainly appears both too much to expect as well as ask for from you. Go back to working for MSNBC or CNN where you might get paid for doing so. The OP made his question area of reference extremely clear not only in this thread bit in others that have led him to what he asked to begin with that you still haven't provided any answer to, instead choosing to engage in churlish childish content here.

 

[Demi-human]

Well instead of being absolutely asinine in plucking a quote completely out of context to coment on not-so-wise-guy, how about something constructive as I said before? It certainly appears both too much to expect as well as ask for from you. Go back to working for MSNBC or CNN where you might get paid for doing so. The OP made his question area of reference extremely clear not only in this thread bit in others that have led him to what he asked to begin with that you still haven't provided any answer to, instead choosing to engage in churlish childish content here.

That’ll learn him! How dare he quote me! He must be a liberal! Yeah that’s it! He should only be telling the new guy only what he needs to know! Next I’ll question his shooting abilities! The rube!


I quoted an interesting comment by another, less dignified, user and answered it.
Don’t post if you don’t want to be quoted.

I don’t know or care what set you off about the information, but you’re acting pretty petty for an engineer...

And if you don’t know higher RPMs have more dramatic effect on varmints, well, there’s a lot that I can’t help you with...

Have a day.

 

[Mr. Zorg]

That’ll learn him! How dare he quote me! He must be a liberal! Yeah that’s it! He should only be telling the new guy only what he needs to know! Next I’ll question his shooting abilities! The rube!


I quoted an interesting comment by another, less dignified, user and answered it.
Don’t post if you don’t want to be quoted.

I don’t know or care what set you off about the information, but you’re acting pretty petty for an engineer...

And if you don’t know higher RPMs have more dramatic effect on varmints, well, there’s a lot that I can’t help you with...

Have a day.

You're acting pretty childish for anyone over age 18 and clearly don't understand petty when you see it every time 3look in a mirror by your own activities. But you certainly can't be expected to live up to any expectations you may hold anyone else to. So I'll add you to my Ignore list so you won't have to deal with my honest assessments to your asininty. You don't want to be called out for childishness, demonstrate it repeatedly in your "contributions".

 

[WisBorn]

As @GooseGestapo mentioned the 7mm-08.
I wonder why a 20" barreled 270 Winchester. I love handy rifles, but I would want a effective cartridge matched with it. A model 7 with a 20" barrel 7mm -08 would be great.

If rebarreling a model 700 with a long action and you have your heart set on a 270 a 22" or 24" barrel will get more out of the cartridge.

This comes from the guy that loves snub nose revolvers

 

[Gtscotty]

It’s not a concern of blowing up anything. Over spinning a bullet can be equally as much a cause of bad accuracy as too slow a twist.

Using a 1:8 they’ll shoot and hit the target sure. But the Accuracy choices will be more limited. That’s all.

I've never seen any data that shows a useable accuracy degradation from making the kind of twist rate change we're talking about, especially with modern bullets, have you? I think the fear of overspinning bullets has become a boogie man at this point, way overblown and for the most part not real. People are running 6.5 twist .223s and 7.5 twist 6/6.5 Creedmoors and 6.5 PRCs out to very extended ranges, as long as they aren't blowing up bullets, accuracy doesn't seem to be compromised. I don't think there's any real chance of negative impacts from going to an 8 twist in a .270, and 8 or 8.5 is probably the direction I'd go. 9 is better than 10, but leaves some bullets on the table for no real benefit.

 

[murf]

there is an excellent john barsness article in the current handloader magazine on the 6mm-06. the shaw 8:1 twist barrel on the rem 700 action will sling a 55 grain ballistic tip out the muzzle @ 4250 fps. not the greatest accuracy (one inch 3-shot group avg.) but no problems with the bullet.

i suggest you go with the 8 in 1 twist. there will be more high bc .277" bullets along shortly.

murf

 

[Archie]

On this subject, I have a couple of observations:

Barrel length is of little or no importance. If the twist rate works for a 16" barrel, the same twist will work for a 30" barrel. Which is another way of saying velocity (above a certain level) has little or no importance. Obviously the bullet has to be spinning at a certain minimum rate.

Weight of a bullet is not the deciding factor; length is the factor. What is confusing is that with a lead core bullet, greater weight is proportional to length. (The only way to get more lead is to make it longer.) However, an all aluminum bullet (which is for explanation, I'm not aware of 'all aluminum' bullets) would be much longer than a lead bullet of the same weight. But requires twist in proportion to the length, not the weight.

Twist rate is not a certain level, but a range beginning at the indicated level. A lot of over spin is better than just a little under spin in terms of yaw and consistency in flight (accuracy). The disintegration of bullets by centrifugal force is quite over stated for general use. Yes, it can be done, but only if one works at it. Generally, hunting or target bullets don't spin fast enough and are built 'tough'.

I suggest if building a rifle with custom barrel, one twist it for the heaviest bullet conceivable. (No one makes, or is likely to make, a 250 grain bullet in .224 caliber. To anyone who objects, my rebuttal is to find a bullet of such weight.) The current standard for .308 caliber rifles of 1:10 is based on the .30-40 Krag–Jørgensen rifle. It stabilizes 125 grain bullets without incident.

 

[Demi-human]

You're acting pretty childish for anyone over age 18 and clearly don't understand petty when you see it every time 3look in a mirror by your own activities. But you certainly can't be expected to live up to any expectations you may hold anyone else to. So I'll add you to my Ignore list so you won't have to deal with my honest assessments to your asininty. You don't want to be called out for childishness, demonstrate it repeatedly in your "contributions".

Well, bless your heart!
Thanks for saving me the effort!
See? You’re not so bad, but you could have just said you didn’t know of any.

Don’t forget your Sertraline today.