Primer/Ignition question?

[Waffen]

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.

Questions, thoughts, comments?

 

[screech]

i had thought that the 215 were ther hotest. i use them. hopefully someone with more expierence will post

 

[bigrich954rr]

how long are you taking to shoot a 5 shot group. sounds like the barrel is heating up and throwing the last shots,

 

[Waffen]

It takes about 10 minutes for me to shoot a 5 shot group. It was 50 degrees out with a 5mph or so wind in my face. I doubt you could even call the barrel warm.

 

[Michael Eichele]

If it is always the last 2 out of 5 and the 1st 3 from a cold barrel are always good, I would say it is a really good chance it is the barrel. Especially if it is a sporter weight. 10 minutes for 5 round in 50 degree air and a sporter weight barrel with a fire breathing dragon is not enough time. Let it cool 5 or 10 minutes between each shot and see what happens.

Federal 215 are NOT the coolest or coldest primers. They are some of the hottest. I doesnt sound like you have a primer issue anyway.

 

[Waffen]

The barrel is a bull barrel. It also is not contacting the stock in any way. You could probably drive a semi through the gap in the barrel channel. I'll slow down next time and see what happens.

 

[Black Diamond 408]

Not the primers, if it were you wouldnt get any groups. Its the bbl moving around due to heat. When barrels do this its usually because the stresses in the barrel react to the heat. This is why barrels are stress relieved, sporter weight barrels are more likely to do this in magnum cals.

 

[sewwhat89]

[ QUOTE ]
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. Questions, thoughts, comments?

[/ QUOTE ]

I would look towards the bedding shifting as you shoot. I had the same problem with my .22-250. The first two or three shots in the .3s then its anyone's guess. The problem was the barreled action was only contacting opposite corners of the bedding block. Some careful stock work by my Uncle, and it would keep 10 shots in the .5s for me. The scenario you gave leads me to blame the bedding. Can't hurt to take a peek and see if you can see wear points on either the bedding job or spots where the blue or finish is wearing uneven on the barrel/action.

 

[Wild_Bill]

Hi i would also check the bedding what did you use? did you have any stress on the action while it was drying. If you dont leave it at least a week without touching it with a large magnum it can give you problems. When bedding onto an alloy block i use my Dremel tool with a sanding drum to fough up the area where the bedding is to go, then i enlarge the cutout for the recoil lug in front and behind to allow for at least 1/8" bedding thickness everywhere. then i place a small drill bit into the dremel and drill 1/4" holes all over the bedding area at diferent angles so when the beding compound is placed onto the stock it is pushed into the holes and bites into the stock and can not shift at all. you can never remove it without grinding it out but this is the way i believe you get the best adhesian and you dont get cracking or slipage of the bedding compound. I also use Devcon Steel for all large kicking rifles.

Cheers Bill
Australia

 

[Waffen]

I used Marine-Tex and a Dremel. I didn't let it sit for a week, just 3-4 days. It seems to work well. I didn't get as fancy as you, however I think it does the job. I would be more worried about that flimsy looking recoil lug than the bedding job. It requires you lift from an exact 90 degree angle to even remove the barreled action from the stock, and it's a tight fit even at that.

The tang, and the bottom metal are also bedded.

 

[edge]

[ QUOTE ]
SNIP
It requires you lift from an exact 90 degree angle to even remove the barreled action from the stock, and it's a tight fit even at that.

The tang, and the bottom metal are also bedded.

[/ QUOTE ]

Two items for me.

1) if you bed the recoil lug 100%, then any bit of dust or lint or anything can get trapped below or on the sides of the lug which may add stress. I have used two layers of tape to the front and sides of the lug...just in case /ubbthreads/images/graemlins/smile.gif

2) Some rifles prefer a floated tang area. Since on most actions the area is small I tend to float anything away from the main action diameter.

edge.

 

[Guest]

This is an interesting subject because I just got rid of a Kimber Varmint in .22-250 due to the same problem. /ubbthreads/images/graemlins/frown.gif
Three shot groups into .385 but 5 shot groups were over 1.25 /ubbthreads/images/graemlins/mad.gif Barrel completly free floated, action bedded. Scoped the barrel and it looked good. /ubbthreads/images/graemlins/confused.gif Tried all kinds of loads in it and finally got /ubbthreads/images/graemlins/mad.gif /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/blush.gif /ubbthreads/images/graemlins/crazy.gif and gave up and traded it in. My new Remington VSF in .22-250 does not seem to have that problem at all. It just shoots good all the time. I now have a lot less hair due to the Kimber but am a lot happier due to the Remington.
My gunsmith said that it was due to the barrel not being stress relived right. It was the only thing we could think of that was left. Good looking gun but looks arn't what make a gun good.

 

[RogerK]

My vote goes for heat. Try a long break between 3 shott groups. I mean get the barrel temp down to ambient temerature and then see what happens.

 

[Michael Eichele]

What Rouge K siad. If that doesnt work, its your bedding.