LR: I am curious...

08 March 2016, 16:23

AnotherAZWriter

LR: I am curious...

ISS:

I would look at the difference in wind drift. Who cares about the drop?

Look at the wind drift of 6.5-284 140 Berger and then identify at what range the 6.5-300 RUM drifts the same amount. I bet the difference is far less than 100 yards. My guess, without looking, is less than 75 yards.

My .308 Win drifts the same at 615 as my RUMs do at 700, and the velocity difference is quite huge.

08 March 2016, 17:23

jpl

quote:
A lot of good accuracy work is being done with the Berger 140gr Hybrid bullet, and I have a generous supply.

Do you have a good supply of barrels and your own lathe? The 6.5-284 has a reputation for eating barrels, so I think a RUM would really fit the bill. But it would be fun to try. How much do you want to shoot it? Varmint hunting and ringing steel at mile? Or is this a 5-rounds-a-year hunting rifle?

Also, with a brake, recoil is often less with a bigger round. Compare a 308 and a 300WM shooting the same bullet. The bullet from the 300 will be slightly quicker which means slightly more recoil, but there will be significantly more gas for the brake to use. So with a good brake the 300 would have less recoil than the 308.

08 March 2016, 17:24

7mmfreak

I'm with AZ on this. You hit a point of diminishing returns. If a fast 6.5 isn't getting it done, a faster 6.5 isn't the answer. I shoot a 6.5 Creed in PRS (although this year I'm shooting .308 in the Tactical Class) and it's great for drop, drift, barrel life, cost, and recoil. My buddy shoot the 6.5-284 for two years, didn't score any better, and killed 2 barrels.

If I need more gun, which only happens for hunting or ELR shooting, I move to a fast 7mm with 175-190gn bullets. If I wanted more and were back home out west instead of NC I would build a .338 RUM or EDGE.

08 March 2016, 20:08

Tyler Kemp

quote:
Originally posted by jpl:

Also, with a brake, recoil is often less with a bigger round. Compare a 308 and a 300WM shooting the same bullet. The bullet from the 300 will be slightly quicker which means slightly more recoil, but there will be significantly more gas for the brake to use. So with a good brake the 300 would have less recoil than the 308.

I'm going to have to disagree there. You may have more gas to use, but in my learning, it's the pressure of the gas that effects recoil suppression. This is why a 45-70 with factory loads, or a shotgun, or other low pressure rounds hardly benefits from a brake regardless of the amount of powder used.

08 March 2016, 23:48

Idaho Sharpshooter

the primary purpose, aside from just enjoying hitting things farther away, is coyotes and Rockchucks.

Probably 300 rounds a year, and at unknown yardages. See them, range them, and shoot at them.

Faster = less wind drift, and higher retained velocity out past 500yds.

I only want to buy one set of reamers, and a barrel every other year is not an issue.

Ever range something waaaaaaaaay out there with your Geovids or rangefinder, dial it up on the scope and see bullet strike and target disentegration? Other side of half a mile is really a buzz...

09 March 2016, 04:28

jpl

quote:
Originally posted by Tyler Kemp:
I'm going to have to disagree there.

By bigger round, I'm talking about the case, not caliber. The OP asked about the 6.5-284 vs a 6.5 RUM using the same bullet, and I mentioned a 308 vs a 300WM firing the same bullet. Basically, more gas makes a brake work better. Check out a 308 vs a braked 300 norma firing an even heavier bullet:

http://precisionrifleblog.com/...ke-recoil-reduction/

09 March 2016, 05:46

Idaho Sharpshooter

jpl,

thanks for the link. George Vais lived here for a couple years, and I did an article on his brakes for Precision Shooting Magazine. He cheerfully walked me thru making one of his brakes, along with all of the details. He said "I have no secrets, just careful machining. If someone reads this who has the talent and machinery to make these, he will likely say 'I can make more money doing rifles. I will just order these from George.' Richard.".

He was quite a guy.

Rich

09 March 2016, 05:47

Idaho Sharpshooter

I am going to just order a set of reamers and gauges and go with the RUM based 6.5mm.

thanks for the observations, and the advice.

Rich

10 March 2016, 18:52

Big Wonderful Wyoming

Rich,

Have you used a ballistic calculator to compare 6.5mm and 7mm VLD Bergers?

11 March 2016, 03:25

Idaho Sharpshooter

I have not. The 6.5's are perhaps the most popular choice these days.

The 7 RUM would be a significant step up in recoil according to my calculator with the 175's and heavier bullets.

11 March 2016, 23:09

Big Wonderful Wyoming

I have a 700 Sendaro 2 in 7mm Magnum, and I am probably going to buy a 700 in 300 RUM.

Yes, the 6.5s are wonderful and don't kick. Hard to compete with that.

12 March 2016, 03:04

Idaho Sharpshooter

oops, forgot to mention I have a Savage 112BVSS in 7 STW.

12 March 2016, 23:43

Big Wonderful Wyoming

The problem with the 7mm Rum is that before you got loads worked up you'd have an accuracy shift. Same problem we had in the 7.82 Warbird.

300 Rum is the least over bore of the LR RUM cartridges.

338 RUM is great but basically a 340 Weatherby in a cheaper offering.

13 March 2016, 06:06

Fjold

quote:
Originally posted by Idaho Sharpshooter:
One more bite of the apple, if you would allow me...?

I am going to barrel one of my rifles in a good 8.5" twist 6.5mm caliber.

A lot of good accuracy work is being done with the Berger 140gr Hybrid bullet, and I have a generous supply.

The 6.5-284 is capable of well under moa accuracy with the velocity right at 2950fps.

The 6.5 RUM has me thinking, it will run that same bullet at 3400fps, supposedly with similar accuracy.

I ran Berger's Ballistic Calculator at both velocities, and the RUM drops -15.24moa versus -22.29moa for the smaller case. Over six feet at a thousand yards.

Do you think that decreased drop, across the board, is worth a couple hundred extra dollars for a two reamer set with gauges, and higher priced brass is a worthwhile trade off?

thanks,

Rich

Rich I shoot the 6.5x284 at around 2950 fps and I get about 1,600 match quality shots out of a Krieger or Bartlein barrel.

At 3,400 fps I would expect about half of that number of quality shots. So, besides the extra cost of the reamer and brass add in the cost of new barrels on a more frequent basis.

13 March 2016, 06:45

Idaho Sharpshooter

thanks Frank.

I have had several people here suggest that I have the barrel chambered for the 6.5-284 to start. If I really want the extra speed, it is pretty easy to rechamber, and the 6.5-284 dies and brass would be simple to sell.

That, and the 6.5-284 would benefit greatly in terms of velocity with the 30-06 magazine box length.