30-06 necked to 7 mm

[grizzlybar]

NFG question would a rifle chambered in 30-06 necked down to 7 mm have a shorter coal than a .280 remington?
30-06 case length is shown to be 2.494 & 270 & 280 case length is 2.540 I know it's not much difference, this probably sounds like a dumbass question but I am trying to decide between 30-06, .280 & .284 the .284 because the coal is shorter except when using long coal's!

 

[Greg Langelius *]

Re: 30-06 necked to 7 mm

Maybe. If so, not really enough to make a difference in accuracy; and reinventing the .280 Rem is not worth any extra trouble that process may entail.

Buy the .280 Rem dies and brass, and concentrate on load development for your specific rifle. Less work, with at least the same benefit in the long run.

Over several decades of handloading, I've come to recognize that there are very few niches left in cartridge design field that heven't already been very adequately filled.

I have also come to recognize that action lengths are always going to pose issues for handloaders, because we like to chase the rifling. Go with the long action and the long case, and live with it. If there is a measurable diffence in accuracy that is based on action length, I really don't care. Whatever that difference may be, it shrinks in comparison to how well one does their load development.

I seriously doubt there are very many handloaders/developers who have ever completely wrung that last little smidgin of accuracy out of their rifles. IMHO, there comes a point where further progress in development simply costs too much overhead in the form of bore wear. One must stop somewhere, and decent accuracy in a barrel that still has the bore life to put it to reasonably long useage is a good place to do that.

Greg

 

[Hellbender]

Re: 30-06 necked to 7 mm

The reason for the longer cases is safety. Keeps someone (or at least slows them down) from loading the wrong caliber in the gun.

 

[Greg Langelius *]

Re: 30-06 necked to 7 mm

Yes, another excellent point I completely overlooked.

The 280's shoulder length is longer than the '06's, the COAL is more dependent on seating depth.

 

[grizzlybar]

Re: 30-06 necked to 7 mm

Okay I will ask the question better!
How important is bullet to rifling distance to accuracy?
I don't want to reinvent the wheel just trying to get accuracy & the coal's are long to get the bullet seated correctly from what some people list!

 

[Greg Langelius *]

Re: 30-06 necked to 7 mm

I try to ensure they either all jump or all don't. Some will try to tune seating depth with more precision.

Bullet curves/ogives will vary somewhat due to manufacturing issues; enough so that you can get different measurements depending whether you measure OAL at the apex, or at some point along the ogive.

Consequently, I expect there to be some variance no matter how I measure and simply seat to my above standard.

I take the longest length of 5 test dummies to reach the rifling and add .010" to that OAL measured at the apex.

Case lengths need not be identical, they must simply be shorter than max.

 

[grizzlybar]

Re: 30-06 necked to 7 mm

Thanks for trying to straighten me out, I'm trying to learn!
I'm not new to shooting didn't have time to get into anything other than work, now I don't have anything but time, but not much money! So how far the bullet jumps doesn't affect accuracy as much as there all the same?

 

[Greg Langelius *]

Re: 30-06 necked to 7 mm

I treat it as if it doesn't, but I could also get an argument on that very easily.

The last two steps I could perform with load testing would be to try substituting primers for the best accuracy, followed by testing seating depths for accuracy.

If my goal was to achieve the absolutely best accuracy at any cost, I'd do that. But that's not my goal. My goal is to achieve acceptable accuracy, which I determine on the competition target. If my competitors are outshooting me, I need more accuracy.

Now I expect to get beaten, and the reasons generally have less to do with my ammunition excellence than they do with my marksmanship skills. Before I go investing money, time, and bore life into more load developement, I make the effort to examine, review, and polish my skills first.

So far, the greatest gains appear to be related to my skills. I figure the rifle still has a few key lessons left to teach me.

Greg

 

[grizzlybar]

Re: 30-06 necked to 7 mm

Shooting skills are as important as anything!
I'm asking the question as I want to re-barrel my Parker-hale rifle, my question may be in the wrong form, you see I'm trying to figure out what caliber I want to re-barrel & re-chamber!
I started out thinking towards 30-06 may still go that way 208 grain a-max is intriguing , but the 7 mm also is promising , especially the .280 remington , but if the longer rounds are going to be hard to get into the magazine then the .284 winchester may get the nod. especially if the shooter is not the limiting factor in accuracy, nor the rifle!
Looking for some direction!!!!!!!!!!!!!

 

[Greg Langelius *]

Re: 30-06 necked to 7 mm

I don't seem to be getting through here. Maybe someone else could be more helpful.

When they do, it would probably help for them to know which Parker Hale rifle you're asking about, and what application you have in mind.

My limited knowledge of the Parker Hales suggests they are chambered for .308/7.62x51, which is a short action caliber. This would appear to make both .30-'06 and .280 unsuitible for magazine length at very least. That would leave .308 and/or/maybe .284 as viable contenders for your approval.

Applications involving greater distance tend to favor longer bullets. This may or may not involve OAL's that exceed magazine length; it's hard to say since seating depth can be adjusted to either fit or not fit the magazine length.

I would not, personally, alter a Parker Hale, as they appear to me to have historic value. There are other, less collectable, rifles available for such alterations.

I hope whoever provides your answer can do a better job than I have.

Greg

 

[Texar2]

Re: 30-06 necked to 7 mm

Stay with standard calibers and pressures with your rifle. TANSTAAFL! Greg, Im going to copy your last post and put it in my sig. lol, I feel your pain.

 

[Greg Langelius *]

Re: 30-06 necked to 7 mm

TANSTAAFL (There Ain't No Such Thing As A Free Lunch).

Amen.

Greg

PS, I don't think it'll fit on a sigline.

 

[grizzlybar]

Re: 30-06 necked to 7 mm

Forgive me for not telling you in the beginning that it's a Parker-Hale 1200 standard, built on , I believe an FN long action chambered in .270 win. The magazine length is 3.40 inches, the rifle was purchased in the 70's , I've seen actions the same as this still being barreled for long range shooting!
I want to stay with the long action like 30-06, 280 !
The reason I worry about the coal & magazine length is some of the load reports for certain loads in certain calibers, i.e.. 30-06, 280 etc. sometimes mention coals longer than my magazine length of 3.40 , so again how important is the bullet touching the lands or three c**t hairs away from the rifling, does this affect accuracy?

 

[Greg Langelius *]

Re: 30-06 necked to 7 mm

It's pretty important of you want to feed from the magazine and the rifling's so far a distance down the tunnel that you can't even get an echo.

In such cases, you're gonna have to make a decision; load to a decent proximity with the rifling and be forced to single feed by hand, or load to mag length, feed sequentially, and take whatever accuracy deficit accompanies that.

This is a question we all have ask ourselves sometime or other. Whether the longer leap to the rifling will have a huge or tiny accuracy penalty is not a predictable factor; you have to try it in <span style="font-style: italic">your</span> rifle, and then decide whether you can live with the leap, or prefer to have to single feed to get what accuracy you think is acceptable.

I chose to arbitraily install a single feed follower and to single feed rounds by hand for my precision match rifle. The others are all loaded to magazine length, and I willingly accept what accuracy I can get that way. It's never been flatly awful, but sometimes it brings a pang of regret.

Understand this, accuracy always involves some form of a tradeoff. Few folks actually chase the accuracy dragon all the way deep down into his lair. Those who do will often pay a penalty in decreased remaining bore life, or relatively finicky loads when the weather changes.

...And that is my last word on this topic.

Greg

 

[grizzlybar]

Re: 30-06 necked to 7 mm

That explains what I needed I appreciate your response so that I can understand!
Frankly if the search engine on the site was better I might not of asked!