Ruger American 6.5 Cm and 120gr bullets

[Ramjet]

Ok I have a stainless Rug. Amer. Predator in 6.5 Cm and a 1 in 8" twist , "stock" with 4.5 x 14 glass . Is this to fast a twist to get sub MOA performance from 120 gr bullets. I only have Speer Gold Dots and it seems like I'll get 4 touching and 1 about an inch away . Things I haven't done:
1. I haven't segregated brass or bullets by weight .
2. I haven't tried adjusting the COAL , I just load to the dimension shown in the manual.
3. I haven't tried neck sizing.

I am using sig brass that is FL resized and Trimmed. I have not done anything to the primer pockets.
Also I am using Rem 91/2 primers and Ramshot Hunter per manual.

Yesterday I shot a "10" shot group 1.4" in diameter . Two were high and two were low . If you measured the 6 in the middle they were .91" .

maybe it is just me.....

 

[dantiff2]

A ton of variables at play with your scenario but I would suggest that after you check all of your screws (stock, base and scope rings) I'd play around with over all cartridge length to find out what your gun likes.
Dan

 

[358WCF]

No. The twist is fine for 120s. I have a similar rifle & 120gr Ballistic Tips shoot very well, usually under 1/2" for 4 or 5 shots @ 100 yds. My rifle also throws a flier in most groups. Not necessarily the 1st, 2nd, 3rd or 4th shot, it's just a random thing, but it is there even in the smaller groups. Playing with seating depth after getting close on powder charge proved to be the final step in shrinking groups. Hint: Longer may be better.

Hunter may be a tad on the slow side with 120s. Varget, 4895, RL15 all have shot well with 120-130gr bullets in my rifle, but have settled on RL16. Not much help, I know. With the better availablity of Ramshot powders, Big Game may be a better choice than Hunter.

Hornady brass is all I have because that's all that was available 3years ago. I've thought about trying Lapua or Peterson, but dont like the rifle enough to spend a whole lot more time & effort trying to make it what it's not... an inexpensive factory sporter for deer hunting & plinking.

Also single loading is a PITA on my rifle. I've started filling the 3 shot mag & slipping one in the chamber before inserting the mag to disturb the gun on the bags less than trying to single load.

 

[Bc'z]

No. The twist is fine for 120s. I have a similar rifle & 120gr Ballistic Tips shoot very well, usually under 1/2" for 4 or 5 shots @ 100 yds. My rifle also throws a flier in most groups. Not necessarily the 1st, 2nd, 3rd or 4th shot, it's just a random thing, but it is there even in the smaller groups. Playing with seating depth after getting close on powder charge proved to be the final step in shrinking groups. Hint: Longer may be better.

Hunter may be a tad on the slow side with 120s. Varget, 4895, RL15 all have shot well with 120-130gr bullets in my rifle, but have settled on RL16. Not much help, I know. With the better availablity of Ramshot powders, Big Game may be a better choice than Hunter.

Hornady brass is all I have because that's all that was available 3years ago. I've thought about trying Lapua or Peterson, but dont like the rifle enough to spend a whole lot more time & effort trying to make it what it's not... an inexpensive factory sporter for deer hunting & plinking.

Also single loading is a PITA on my rifle. I've started filling the 3 shot mag & slipping one in the chamber before inserting the mag to disturb the gun on the bags less than trying to single load.

Accurate powders are often overlooked, I agree with Big Game probably being better suited.
With 123's I shoot listed slowest to fastest in burn speed by a inaccurate chart.
RL19 123 Amax
AA2700 123 scenar
IMR 4166 123 Scenar
All with CCI 200, magazine fed so they are jumped considerably in my application.

 

[Larry sigmon]

Bullets may be to light for the twist ? Mine likes 143 and up

 

[Fyrchief]

I also suggest a better trigger first and then a better stock. My Ruger American 6.5 CM is sub 1 MOA with 107 through 140 gr. bullets with a Timney trigger and Boyd’s stock.

 

[Coyotefurharvester]

Find the best seating depth for that bullet. Watch you trigger/hold and bag setup so rifle travels consistently the same during recoil.

 

[Ramjet]

Frychief - I installed the new Timney today and set it at 2 1/2 pounds. I think you are right . A good trigger will help more than anything. It will be a week or two before i can shoot again.

 

[Ramjet]

PS : I ordered some more bullets. I got some Hornaday 129gr Flat base interlocks and 123 gr SST's.

 

[mauser284]

Ok I have a stainless Rug. Amer. Predator in 6.5 Cm and a 1 in 8" twist , "stock" with 4.5 x 14 glass . Is this to fast a twist to get sub MOA performance from 120 gr bullets. I only have Speer Gold Dots and it seems like I'll get 4 touching and 1 about an inch away . Things I haven't done:
1. I haven't segregated brass or bullets by weight .
2. I haven't tried adjusting the COAL , I just load to the dimension shown in the manual.
3. I haven't tried neck sizing.

I am using sig brass that is FL resized and Trimmed. I have not done anything to the primer pockets.
Also I am using Rem 91/2 primers and Ramshot Hunter per manual.

Yesterday I shot a "10" shot group 1.4" in diameter . Two were high and two were low . If you measured the 6 in the middle they were .91" .

maybe it is just me.....

No it is not but that does not mean that your rifle will like 120gr. bullets either. Short of a bullet flying apart because the twist and velocity are too high for the jacket to hold together there is no such thing as "over stabilization". That does not mean that there are not ideal twists for different length bullets and bullet shapes. Some specialized use situations call for hugely handicapping a rifle with a twist so slow it will only shoot 1-2 bullets well. We see this sort of compromise in the 30BR because it is really designed to do one thing well and only that one thing. It does not need to be able to shoot every possible weight and bullet design available for 30cal chamberings 1:17 or 1:18 twist in a 30 caliber!

I wish I knew what knuckle-head brought the idea of "over stabilization" into the realm of the average shooter and hunter. If anything this really opposite of intelligent idea has held back and hurt the average factory rifle buyer. I ams ure it had something to do with bullets flying apart inthe 220 Swift. The same rocket scientist type that thought the speed of sound could not be broken or it was impossible for man to fly.

The 8.6BLK has a 1:3 twist. The twist is so fast the bullet flys out backwards after it leaves the muzzle makes an arc in the air and returns back to the barrel like a boomerang. Last I checked they were only using monolithics so that they do not have to worry about the bullet spinning itself apart.

The theory of nose high bullet issues with drag looks good on paper and sounds good. THe problem is you can not get it to convincingly rear it's ugly head. So that makes it theory at best but not at all proven to be an issue in the real world. What has been proven is that under stabilizing bullets is far worse and always shows up at long range. Nothing makes a rifle obsolete as fast as a slow twist barrel does.

Bullet design is the real problem not weight.

 

[mauser284]

P.S. I would suspect barrel heating or a break in the fundamentals of shooting with volume of fire.

 

[JB10]

Although those rugers shoot very well out of the box, i feel the stock is a weak point. My 204 i left in original stock, my 6mm creedmoor i changed. A friend's 6.5 cm also changed stock. All 3 shoot 1/4 in groups. I'd be looking at the stock or if you are slightly changing ur hold. That can also produce flyers.

 

[CJ6]

Mine had 3 different pressure points in the stock...Check for clearance between stock and barrel and fix it. It made a world of difference in mine. From 2.5 inches down to .4 with minimal change when barrel heated up.

 

[Ramjet]

Ok I have a stainless Rug. Amer. Predator in 6.5 Cm and a 1 in 8" twist , "stock" with 4.5 x 14 glass . Is this to fast a twist to get sub MOA performance from 120 gr bullets. I only have Speer Gold Dots and it seems like I'll get 4 touching and 1 about an inch away . Things I haven't done:
1. I haven't segregated brass or bullets by weight .
2. I haven't tried adjusting the COAL , I just load to the dimension shown in the manual.
3. I haven't tried neck sizing.

I am using sig brass that is FL resized and Trimmed. I have not done anything to the primer pockets.
Also I am using Rem 91/2 primers and Ramshot Hunter per manual.

Yesterday I shot a "10" shot group 1.4" in diameter . Two were high and two were low . If you measured the 6 in the middle they were .91" .

maybe it is just me.....

Ok so I finally got back out with the 6.5 . Put in a new Timney trigger and added a Magpul Hunter Stock. Attached are pictures of the targets each with 2 groups I shot at earlier this week. The load ing is:

Hornaday Brass
Federal 215 primer
40-41.5 grains of N203B in 1/2 grain increments
123 Hornaday SST

 

[k80skeet]

I have a couple of 6.5 Creedmoor's one is a Savage Model 14 ss 22" barrel the other is a Cooper with a 26" barrel both are 1 in 8 twists. Both of these rifles will shoot sub half inch 5 shot groups. With the standard factory load that Hornady used to print on the boxes of factory ammo. Of course that was years ago with the 6.5 Creedmore first was made. Well here is the (2) factory loads the made and this is the load their Factory Shooting team used to win a lot of matches. I have done a lot of testing through the years and I couldn't find anything that shot any better over a long strings of shooting.

Bullet: 120gr Horanady "A" Max
Powder: 44.5gr H4350
Primer: Federal #210M
Case: Hornady

Bullet: 140gr Hornady "A" Max
Powder: 41.5gr H4350
Primer: Federal: #210M
Case: Hornady

 

[mauser284]

Bullet weight is like show sizes or pants sizes. It is a great place to start but by itself is almost meaningless you need to try it on before you buy 5 pair. So try various weights and designs and see what your rifle likes.

Barrel and action dynamics while some things are grounded well in science and engineering at other times it seems like voodoo!