Gentlemen,

I recently found a load that I can FINALLY get to shoot out of my Rem 700 in 300 RUM, however it seems to be a bit inconsistent.

I just got back from the range today where I fired 30 rounds of the exact same load. Temps were about 50 degrees. I can put 3 rounds in the exact same hole at 100 yards without problem, however when I shoot a 5 shot group at least two of the rounds are "flyers". I can't really explain it. I KNOW it's not me, I've shot much bigger and badder, the shots feel good as soon as I pull the trigger, however when I look back down the scope I see a flier 1 inch away from the other 3 rounds.

I got to thinking about everything that would affect the situation. I know the mounts/rings are good. I know the scope is good. I know the stock/rifle contact is good. The load seems to be good as it will one hole 3 rounds; I mean groups in the .2's .3's CTC.

I moved over to the 200 yard range, same thing. Groups about .5-.6 for 3 rounds, but when I shoot 5 it opens the group up to 1.2-2.0

I was wondering, I had heard that Federal GM215M Primers were the "coldest" of the magnum primers. Any truth to this?

I've never experienced an ignition problem in a rifle before so I don't really know what to look for. I do know when setting off 98gr of powder it wouldn't be hard to get them. I was wondering if others are using 215M primers on big mags, or if they move to something a bit hotter say a WLRM?

The rifle is basically a factory stock 700 Sendero. I've glass bedded it, added an aftermarket trigger and tuned it down to about 1/2lb. I've got a Leupold 8.5-25x50LRT sitting on top.

The load I was shooting was:
165gr Nosler Accubonds
98gr H-1000
Remington Brass
Federal 215GM Primers
3.63 OAL

Questions, thoughts, comments?

1. As barrels get hot, they can walk.
2. As barrels foul they can walk, usually up and down.
3. A big cartridge like a 300 RUM bend the whole system a lot more than, lets say, a .223. 1.5 MOA with a big horse like that is not bad.
4. Primers are easy to blame. And unlikely to be the problem. Stick a chronograph out in front of you and measure the velocity of your string. If you see ES' in hundreds of feet, well something is wrong.
4. How do you know it is not you?

If I was sitting behing a cannon like a 300 RUM, my teeth would be clinched, my eyes would be closed, and my body would be bucking around shot three. Might even be around shot two. You got that good of a flinch control?

Shooters are the biggest source of error in the system, assuming good barrels, good bedding, good bullets. And it is subtle. A little position change, a little tighter grip on the stock, the stock not at the exact same point on the shoulder, your elbows a little different location on the bench, all this stuff will open your groups up. Then add the fun of firing a cannon, and again, how do you know it is not you?

Slamfire,

I'm about as sure as sure can be it's not me. I can shoot a 338-378 with a custom tube into .5 all day long with the right load. I've been schooled on big rifles, and they really aren't that big of a deal to me.

The barrel was kept cold. It was 50 degrees with a slight wind in my face, and I was under shade. The barrel was kept quite cool. I was also rotating with other rifles.

As for fouling, I don't know. I fired 6 rounds of 5 bullets each round. It did the exact same thing each time. I had absolutely cleaned the snot out of the rifle prior to shooting it today. I'd run 4-5 treatments of wipeout, CR-10, and hoppes down the barrel. If it started doing it after the first volley of fire, then I would certainly say it's fouling, but it's just weird that it did it every time.

I unfortunatly do not know the ES on it because I don't have a chronograph I really need one because it's a huge help, but it's possible to develop a good load without one.

I'd ask someone else to shoot the rifle, but I don't know of many people at my range who I could trust to shoot a consistant group with a .223 let alone a .300RUM. The one guy (range buddy) I know could has been out of town on business so changing shooters at this point I doubt would tell me much.

[QUOTE]Originally posted by Waffen:
Gentlemen,

I moved over to the 200 yard range, same thing. Groups about .5-.6 for 3 rounds, but when I shoot 5 it opens the group up to 1.2-2.0[/QUOT

So what's the problem? Looks just fine to me. roger

Primers are the absolute last thing I'd look at when it came to flyers. If the primer isn't doing a good job lighting off the load, you won't get any good groups at all. I've heard the fed 215 is one of the hottest primers, and have heard nothing to indicate the match primer is cooler than the std 215.

5 shot groups are generally 30% larger than 3 shot groups.

Flyers are generally related to stresses being released, and can be caused by a stressed barrel heating up, an action that is stressed moving, the barrel contacting the stock, etc. It could also be the scope, as known good scopes can/do crap out at inoportune times.

You could have also just had an off day. People are like rifles, when the are stressed they don't shoot well.

I just read an article on neck tension creating problems like this. (should say I am reading it) not sure what your sizing set up is or if you turn or ream your necks or if it "the" problem???

Just a thought for you to think about.

Just exactly how many time are you going to have to shoot this deer, elk or what have you with a rifle that consistently puts its first three shots in one hole??

For the intellectually curious, I have experienced differences between magnum and standard primers and accuracy, but not differences in the range you describe with shifts from WW to FC magnums.

I think folks have really given you some good scoop, but I'd also suggest that you carefully examine your bags (rest) and rifle to make certain that you are getting back to the same point of contact on the stock. This will cause changes.

As mentioned above, just adding the added shots to the group will open it up. A five shot group in the range you are describing from a factory rifle ain't bad, and you will get the job done with this rifle before you get to the fourth shot. Kudude

Kudude,

I don't plan to hunt much game with this rifle, as it's pretty much overkill for anything in Texas. It might be fun to pop a hog with a 300 RUM but for deer I have other guns that will do the job just as well and are a little more portable. My 300 RUM is a range gun 99% of the time.

As for the rests, I think I get back on them consistantly all the time. I probably shoot maybe 40 weekends out of the year, from this same rest and bench setup. I realize it's possible to mount it wrong, but it's almost become "muscle memory" to mount a gun at the bench. I have the same routine every time, but anything is possible.

Waffen:

You have already bedded your rifle, so that has thrown me for a loop. Recently I bedded my Ruger M77 Tactical, the groups were being thrown left and right. Bedding really fixed the flyers. I am assuming you did not bend the action as the bedding compound was hardening.If you did in any way, as that action heats up, it will try to move.

Scopes are very hard to diagnose. But I have had reticles bounce around. Of course, loose scope mounts will cause all sorts of fun. Maybe the scope mounts are off axis and as the rifle heats up, the scope bends.

Could be the rifle barrel. I have one Swedish Mauser, as the barrel heats up it walks about 12 inches at 100 yards. No joke.

Still two inches at 200 yards is just excellent with a large caliber rifle. If you want .5 MOA accuracy with the thing, you should start at increasing the stiffness of the system. You will need the heaviest contour barrel you can on the receiver and a big heavy stock. Increasing stiffness will reduce

Is it always shots #4 & 5 that are the fliers or is it #1 & 2 and the rest are good?

Had a Mauser conversion in .270 with Fajen stock, magnaported, glass bedded and free floating barrel. It would consistantly shoot sub-MOA groups with several different bullets. Well, except for the first shot in a cold barrel (clean or fouled made no difference). It would shoot 6" to 8" high and left every time. Tried everything including explaining to the gunsmith that firing a shot into the dirt is really not a good way to start hunting each day.

Finally resolved the situation by giving the gun to my son-in law.

Mike: You had an extreme example of barrel fouling.

I shoot a lot of highpower competition, would shoot every week if there was a match. I have started many a long distance match, same rifle, same range, same ammo, last sight settings. First shot out of a clean barrel is no way near the middle. Can be anywhere, usually low. By the third shot the bullet is usually in the middle. But as the barrel fouls and gets hot, I have to increase the elevation by a click or two. At long distance windage is whatever direction the wind blows, but elevation is only affected by gravity.

You are kind up the creek when you get 8" offsets.

Incidentally, my experience makes me doubt the marksmanship of people who claim 600yard or 1000 yard kills. Yes, they did hit, but I bet the trigger broke when the sights were way off target.