Freakish fliers

[Garrum]

If its not one thing, it's another.

First, the offending rifle. It's a Remington 700 Sendero SF, chambered in 7mm Rem Mag. The sighting is done through a Simmons 3.8-12x44mm Aetec mounted in Redfield style rings and bases. I tuned the factory trigger down to a crisp and consistent 3.5 lbs.

Second, the possibly faulty handloads. They are 139gr Hornady SST's over 66.5 grns of RL22 in Winchester cases, lit up by Federal GM215M primers. The bullets are seated very close to the lands. I am very careful about weighing powder charges. The dies I am using are Redding Competition, the ones with the Titanium bushings. I don't, however, have a concentricity gauge to check runout with. I also don't have a chronograph to check velocity deviation.

The problem is this. When I fire a group, I often get two rounds very close, say .4 or less, but the other round is sometimes up to an inch and a half away, but usually closer to an inch. There is no set order in which the rounds impact. Sometimes, the first round is the flier, others, its the second round, and just as often, the third.
But, just to cause me grief, sometimes I'll fire a group without even a hint of a flier, just a tight little cloverleaf of about .5.

Now, I realize that it could be crooked ammo, wide velocity spreads, faulty scope, or a bad bore. The bore looks pretty good though, very minor looking tool marks. The crown looks OK as well. The reason that I'm posting this long, drawn out question, is that I thought that maybe some of you fellas had seen a rifle do something similar and could enlighten me.

As always, any help or info is appreciated.

 

[Dave King]

Does this scope have parallax adjustment and if so are you setting it carefully?

Have you fired these rounds only at 100 yards? If so, you may want to try them at 200 or further.

Do factory rounds exibit the same pattern?

Have you had other good shooters try the rifle and if so do they get the same results?

If the runout is very significant you should be able to see it with the naked eyeball. Slowly roll the loaded rounds across a clean & flat surface observing the very tip of the bullet, if it wobbles it's got it bad.

Are you shooting over a rest on a bench or from a bipod in the prone position? If from a bench be careful that the front swivel stud isn't contacting the rest on recoil.

This should get us started on a fix for you?

/r

 

[kidcoltoutlaw]

if you are pulling the gun into your shoulder at 30 pounds with one shot at 25 the next it can make a difference.the key is to do everything in a way that can be repeated,shot after shot,thanks,keith

 

[Garrum]

Yes, the Aetec has an AO, and I do my best to eliminate all apparent parallax. I have fired groups at 200 and 300 yards, and they all show the same tendency to throw one round away from the others.

The factory rounds that I have tried (Hornady) group about 1.5 inches, and make pretty round groups, with about equal spacing between rounds. The throat in my barrel is slightly long, and I figure that factory rounds just can't make the leap accurately.

I rolled my handloads like you suggested, and I didn't see any wobble, but it could be so slight that I just can't see it. I really need an RCBS Casemaster.

Unfortunately, no one else that I shoot with has any ambition to shoot precisely, and most of them flinch when firing a .308 Winchester. Their idea of sighting in a rifle is to lean over the hood of a truck at fifty yards, and adjust the scope after every shot. So I'm afraid that letting any of them fire the rifle would simply be a waste of my powder. Sigh.

I shoot off of a bench, over sandbags. I place the front bag a few inches in front of the action, so the sling swivel isn't contacting during recoil. However, the rear swivel does contact the rear bag. Could the rear swivel be part of the problem?

I'll pay more attention to the way I pull into my shoulder next time I go to the range, and I see if that helps.

Thanks for the help so far, maybe between smarter heads than mine, this problem will get squashed.

 

[Dave King]

Thanks for the reply.

The fact that the factory rounds group in a consistent pattern is a good indicator that it may be your rounds. Also the fact that the rounds exibit the same flier tendancy at longer ranges point to something.

If the rear rest were the problem it should show up in the factory round (if you were shooting them over the same setup).

Having many non-precise shooters around is a standard condition, you're in the same boat as many of us but somewhere near you is a precision shooter and maybe we'll find him here for you.

Have you played with the seating depth?

Can you find a box of Federal Gold Medal Match ammo (I don't even know if they make it for the 7mm Rem mag.) to try?

Are all you cases from the same LOT?

Are you careful to get back into the same position after every shot? Same shoulder pressure has been mentioned, how about cheek weld, grip tightness? Do you hold the rifle's fore end with your "off" hand?

 

[Garrum]

The factory rounds were fired the same way as the handloads, over the same bags on the same bench, so I guess the rear swivel isn't the culprit.

I have experimented some with seating depth, but if the bullet is seated any deeper, overall accuracy suffers. I even seated them down to the cannelure and crimped the bullet in the case, but groups were 2.5 inches with that set-up, since the cannelure on SST's is very high on the bullet.

As far as I know, Gold Medal ammo only comes in .223, .308, .30-06, and .300 Winchester. (Darn Federal, ignoring the .284 bore.)

The brass I'm using is Winchester W-W Super, bought in a 50 piece, bulk bag from Midway USA, so I assume it's from the same lot, but who knows if Winchester is careful about keeping brass lots together.

Just like pull tension, I really didn't think about getting the same cheek weld, but my grip is fairly consistent, as I try to put my finger on the trigger the same way every time. I'll make sure my cheek goes to the same place every time from now on. My off hand goes back under the stock to hold the rear bag.

You have a point about the evidence pointing to my handloads, and I have been thinking the same thing for a while. I just thought that I would check to see if maybe some of you serious shooters had seen a similar problem in another Sendero.

This may, however, be a case of me trying to put the blame on the rifle, when it is really the ammo's fault.

 

[chris matthews]

I wouldn't write off the rifle yet- a buddy of mine at school brought in his sendero in .22-250 for a good cleaning. Upon inspection he noticed the rifling did not come all the way out to the crown on one side of his barrel. After recrowning and a bedding job we took the rifle to the range. He was getting the exact same situation as you- with Winchester Supreme ammo (50gr Ballistic Tips) Two shots would be almost touching or touching and the other would be off. The rifle was still shooting 1/2 to 3/4 moa but could have been tighter except for the flyer- this was the same for 100, 200 and 300 yards. After several tries, he asked me to shoot to make sure it wasn't him- I fired three 3 shot groups with the exact same results. We tried everything- nothing would help. If I was to make a scientific wild *** guess it would be the barrel has a stress point in the steel- I believe Remington barrels are hammer forged- I would suggest having the action and barrel cryo-ed to stress relieve it. Couldn't hurt and at best it might help.
Just another angle to consider...

 

[Steve Shelp]

Before you go spending a lot of money trying different things on the rifle, try the simple solution that Dave King had pointed out above in his very good evaluation of your problem. I would have to agree with him in that, it's your ammo, or more specifically the powder/primer/bullet combo. Just because a load gives 2 tight and one loose shot doesn't mean it's a good load with a flyer. Be honest with your self here. One of those 2 shots together could be the "flyer" and the other 2 shots far apart could be the normal load. You just simply don't know.
I would try a different powder. In any 7mm Mag I've ever shot and loaded for if IMR4350/IMR4831/ or H4831 didn't give good consistant results, I started looking at the rifle for problems. We had a match at the NC 1,000yd club yesterday and 3 of the 4 Factory class relay winners were firing 7mm Rem Mag in Remington 700 rifles. I talked to each one of them because the 7mm Mag has come on strong in the last couple of matches to knock off the 300 Win Mag as the Factory Class "King of the Hill". They all said they were using IMR4350 with 150 and/or 168 MK bullets. The match report says otherwise but I saw the loading cards in thier ammo boxes.
Also I would suggest not using the GM215M primers. You don't need a magnum primer just becasue your case has magnum stamped in the case head. I use GM210M primers in my 338 Lapua Improved mag down into the 40F temperature range without problems at all. And that's igniting 90+gr of very slow powder. In my 300 Win Mag I had to drop down from the GM215M to a GM210M to get rid of the vertical flyers at long range and bump my load up 2 grs to compensate for the velocity loss. Just a suggestion.

But play with your powder/different wgt loads first in .5gr increments until it consistantly shoots tighter groups. The Remington Senderos in 7mm Mag and 300 Win Mag are shooters. Yes they do have problems now and then, but I've seen to many shoot right off the shelf to give up on yours just yet.

Hope this helps,
Steve

[ 07-14-2002: Message edited by: Steve Shelp ]

 

[CatShooter]

I would agree with Steve...

Three shot groups are only good to check zero at the hunting camp. The are telling you NOTHING!

Start shooting 5 (or better yet, 10) shoot groups. This will tell you what the gun is really doing.

Also, you might consider getting the action glass bedded. I have glass bedded many of these H-S stocks, and every one of them improved a LOT! Winchester glass beds the H-S stocks at the factory, before they are sent out... that should tell you something about the H-S "metal to metal" fit

CatShooter.

 

[Garrum]

I'll see what happens then next time I go to the range, being very careful about pull tension and cheek weld. If that doesn't seem to make a difference, I'll try changing powders, but, wouldn't you know, I just bought a whole carton of GM215M's three days ago. I would hate to have 1000 primers go to waste.

On the other hand, if I do end up changing powders and it still acts this way, I'll try a box of GM210M's.

As far as glass bedding the action, I've thought about it, but am a little leery about doing it, having never bedded a rifle before. The thought of screwing up an expensive stock makes me queasy. The only gunsmith near me is geared towards shotgun work, and doesn't 'tweak' rifles. Is Acraglas hard to use properly? If not, I may grit my teeth and do it myself.

I see your point about shooting five shot groups, and I believe I'll start doing five's instead of three's to get a bigger picture of what's going on. But, wouldn't ten shot strings be extremely rough on the barrel?

In any event, it's nice to see so many folks come out to help someone they don't even know.

[ 07-14-2002: Message edited by: Garrum ]

 

[Warren Barrett]

I second the load change also. The Fed. 210GMM primer will work very well. You may need to try some H4831, IMR7828, R25, or some other powder with slow burn rates with some other bullets. Sometimes you get a bad batch of bullets. It would be wise to try some heavier bullets also that has been known to be very accurate like the 150gr. Nosler ballistic tip. The swivel stud needs to clear your bag. You should be able to screw it out if necessary. I would add this to the recommendations that the other guys requested before paying a smith to work on it. Hopefully you`ll be surprised with the results.
One more thing, I would try the loads with the bullet hitting the lands pretty hard.

 

[Steve Shelp]

Garrum,
I've never used the PAM method but know of others that have. Shoe polish works also. The theroy is that this stuff is a thinner coating on your barreled action so the end result should be better fit. Me for hunting guns when using Acraglass, I've always stuck to the supplied release agents and some vaseline on the screws and threads, with clay to fill in all voids in the action.

Now that you have it bedded, is the barrel floated? Some say to bed the first few inches and all sorts of various ways. But my theroy goes like this... if NOTHING is touching the barrel then it can't have any pressure points after heating up or pressure on the forearm while firing. So I always float a Remington barrel 100% with clearance on the front of the recoil lug also. This has always worked for me. Good job taking this on yourself. As you can see it's not that difficult and your gun can only be better. If it's worse after the bedding job, then it was done wrong and you'll learn something. Plus Remington's are probably the easiest to start with for the first bedding job.

H4831SC is the short cut version of the old standby H4831. They advertise it as interchangeable between them. But as usual the typical safety standards apply when changing a component. But to say SC is better than the standard or vice-versa, I've never seen any evidence. I have both types and shoot both in various rifles.

Good luck and keep us informed!
Steve

[ 07-19-2002: Message edited by: Steve Shelp ]

 

[Garrum]

No, I didn't float the barrel totally. The reason is that all the pictures that I have seen in the various firearms magazines that I have, show a small pad of bedding forward of the recoil lug. And being unsure of myself, I did it like that, thinking that it was the right way to do it. And it may do just fine. I hope.

I guess if it goes berserk I'll borrow my buddy's Dremel tool and cut away the parts that touch the barrel, but I really hope I don't have to.

I noticed after I put it all back together, that when I worked the bolt it felt and sounded different than before. More subdued sounding, and more solid feeling. Kind of eerie after the rattle and clatter that I heard before the bedding.

Anyway, thanks for the info about the powder Steve. If I do totally change loads, that is probably what I'll use.

 

[Garrum]

Update.

I finally got to the range on Wed., and did some shooting. I had rounds loaded with RL-22 and IMR 4350. The rounds loaded with RL-22 acted similar to what they had done before, even when shooting five shot groups. One group, as an example, had four rounds in .45 in. and a flier a little over an inch away.

The rounds loaded with IMR 4350 were in new cases, so the evidence isn't conclusive, but they seemed to group about the same, and they also showed a slight tendency to produce a flier or two. I'm going to shoot a few more groups with fired brass next time I go to the range to see if that helps.

While I was at the range, I started talking with the range officer while my rifle was cooling between groups. I asked him about bedding, specificly, is it hard to do. He said that it wasn't bad at all. He also said that Pam (the cooking spray) is a great release agent. So Thursday I bought a package of Acraglas Gel, and bedded my action as per the instructions. That tip about Pam was a little too far out for me, so I just used the release agent that comes with the kit. Other than having to whack on the stock for ten minutes to get the action out, it went pretty well. I may have to redo the rear tang, but I'll wait and see.

When I go shooting again (after a week of curing time) if it still doesn't shoot like I think it ought to, I'll change bullets, primers and powder. Maybe Hornady 162gr A-Max bullets with GM210M primers and a suitable charge of H4831.

As an aside, the only H4831 around here is called H4831SC. The SC supposedly stands for Short Cut. Anyone ever use this before? Or has it always been that? Also, was that guy just blowing smoke about the Pam?