308 winchester + 5R Rifling

[Herb in pa]

I wondered how the 5R rifling would treat a cast bullet. Rifle is a Remington 700 M24 clone that was a special order circa 2000. Stainless steel barrel and action with 1 in 11 1/4 twist designed to shoot the 175 Sierras. I swapped out the infamous J Lock bolt shroud, installed a Timney Trigger and added a Decelerator recoil pad. I loaded up 40 rounds of the RCBS 165 Sil sized @ .310 with some 2400 and Winchester Large Pistol primers. Results as follows @ 100 yards.
First 2 groups from the left used 20 grains of 2400..........first group went 1.510" with 9 in .962", second group went 1.366 with 9 in1.091. Groups 3 and 4 used 20.5 grains of 2400 group 3 went 1.192" with 9 in .698" while group 4 opened up (should have left the barrel cool a bit went 1.448" with 9 in .950". Intend to increase the next test using 22.5 and 23 grains. Groups @ 100 yards

 

[MW65]

Nice experiment!! Have had great luck with the 788, using a little heavier bullet... rcbs 30-180 fn, and using 2400 powder. Would have to review my notes, but I was probably down around the 14-16gr range... great for popping silhouettes and general fun.

Enjoy!! -Andy

 

[CZ93X62]

VERY PROMISING START.

All of my time spent behind those M24geries (3 in number) was spent shooting factory Federal GMM 168 grain Sierras. Results were quite decent, about 0.6-0.8 MOA at 100 and 200 meters. 3 shooters, 2 days, 260 rounds. For out-of-the-box rifles at a working-class price point, we were pretty impressed.

10-shot groups is courageous--cast bullet polygraphy on a rifle range. One flyer does not a habit make.

 

[Spindrift]

Very nice shooting and results!

 

[Ian]

This is the only recorded evidence I have of my 5R 11" barrel. It is a Rock Creeck on a Savage 111, .308 Bisley chamber. Target was shot alongside my 18" LR-308 for comparison, the velocity from the LR was 2464fps average of 10, add 6" of barrel for the 5R and figure the velocity was 26-something.

5R shoots but I wouldn't say it is any significant advantage for cast bullets.

 

[Rick]

Can't argue a bit with those groups but I suggest also trying the RCBS 180 SIL. With what I've done with it that bullet just seems to know where to go. You may be surprised.

 

[Ben]

Very impressive ! !
I also have a 5 R barrel in 30-06.
Also super accurate.

Ben

 

[CZ93X62]

There is a lot of theoretical talk about the advantages and down-sides of the various rifling forms. I have barrels with 3-groove, 4-groove, 5-groove, and 6-groove patterns in some numbers, and I don't think the form or the groove count matters a bit. Twist rate needs to support its bullet length, but if the barrel is uniform in dimensions and finished properly, chances are it will shoot well. Bummers happen, I've had a couple--but even those bummers shot at least ONE bullet fairly well. Throat problems have been far more frequent offenders than have bore issues IME, and those throat issues got handled to good effect.

 

[Ben]

Words of wisdom.....................

 

[harrympope]

It's refreshing to see somebody shoot multiple 10 shot groups. That's pretty good repeatable accuracy and the point of impact seem to be very consistent.

You may have better luck than me but when I went much above 18 grains of 2400 in my 308 rifles my accuracy did not improve.

 

[fiver]

notice his primer choice.
subtract about 1-1 1/2grs for rifle types.

where 5R excels is in not damaging the jacket of a copper wrapper when your using it as a hunting rifle.
the only 5R rifle I have is my 7X57 ICL and I specifically ordered that barrel, and had the throat cut for the Hornady 139gr interlock,,,,, the rest was left up to the smith.

 

[Herb in pa]

VERY PROMISING START.

All of my time spent behind those M24geries (3 in number) was spent shooting factory Federal GMM 168 grain Sierras. Results were quite decent, about 0.6-0.8 MOA at 100 and 200 meters. 3 shooters, 2 days, 260 rounds. For out-of-the-box rifles at a working-class price point, we were pretty impressed.

10-shot groups is courageous--cast bullet polygraphy on a rifle range. One flyer does not a habit make.

Not sure if I got lucky with this rifle as it was a special run, came with about 95% bolt lug engagement. Also wears an HS Precision stock from the factory. It really thrives on the 175 grain Sierras.

 

[Bret4207]

I admire anyone that uses 10 shot groups. I've never been on the 3 or 5 shot bandwagon. 10 groups of 10 really lets you see whats happening! Well done.

 

[Kevin Stenberg]

Herb where did you get a barrel with an 11 twist?
I passed on a Shillen 11" twist before Covid but haven't seen one since at Midway.

 

[Herb in pa]

Herb where did you get a barrel with an 11 twist?
I passed on a Shillen 11" twist before civid but haven't seen one since at Midway.

It came on the rifle from Remington, it was one of their 5R Milspec barrels designed for the 175 grain Sierra MK bullet.

Remington 700 Mil-Spec 5R: Bargain buy for a thousand-yard rifle :: Guns.com

To many shooters, the allure of long-range rifle shooting is irresistible, but what isn’t so glamorous is emptying the life savings to afford such a rifle.

www.guns.com

 

[quicksylver]

Just a suggestion drop down to around 16 grains of 2400 and work your way up to 17, in .2 or.3 gr.increments, wouldn't surprise me if you got some mind blowng groups around 16.7 grs LRP. of course

 

[Ben]

Again, some great advice.

 

[STIHL]

I’ll be interested to see those groups from 16-17 grains. If it can improve on those fine groups from above l, I want to see it.

 

[Herb in pa]

Another trip to the range yesterday. I shot the 21.5 grains of 2400 and then 22
grains. Used the same target for comparison, the lower groups are the new loads.
From the left..............1st group @ 21.5 - 1.785" (9 in 1.117"), 2nd group @ 21.5 - 1.855" (9 in 1.054"), 3rd Group @ 22.0 - 2.305" (9 in 1.037"),
4th Group @ 22.0 - 1.401" (9 in 1.042"). Perhaps need a little more QC in bullet sorting............

 

[harrympope]

Those groups are pretty good but a standard match load for the 30-06 and 2400 for years has been 16 to 17g. Like the poster said above I think back it down. I shoot 14 grains with a 180 grain bullet in my savage 99 308. This gun is not near as capable as yours but ten shot groups are often a couple inches with a Four-power scope.