Home Forums Hunting & Shooting Hunting Rifles Low mount rings and ejection problem?

Hello,

Wanted to get some opinions. I have a couple of Cooper M52 rifles that both have Leupold VX-III, 2.5x8 scopes in low rings on them. I have noticed that occasionally I will have a failure to eject spent brass, leaving it lying in the raceway. Seems to occur mostly at the range, have not had it happen in the field. Anyway, last weekend I was at the range and it again happened a couple of times and as I was looking things over, I noticed that the underside of the scope and the right turret cover are marred up a bit. Makes me think that the brass it striking the underside of the scope and causing the failure. Anyone had this problem? Should I just buy a set of medium rings and see if it helps? Thanks.

This was a very common problem with the Remington 788 too. If the case is striking the scope turret and falling back into the action one way to fix the problem is to rotate your scope in it's rings 90 degrees counterclockwise. Of course your elevation knob becomes windage and you windage becomes elevation. It's a cheaper fix than new rings. Good Luck, and let us know what works for you.

Will also allow you to keep the low scope mounting.

Von Gruff.

I'd use whichever height ring that gives you a natural line of sight straight down the center of the scope tube when using good form with a proper spot or cheekweld. Sometimes we tend to chase after the lowest mount combination we can make mechanically fit without giving any thought to the design of the stock or good form. When I'm on the fence for ring height, I use an alignment rod which has a small hole bored down the center through its length. I use the height combination that allows a natural line of sight to see through the small hole when using good form. I can tell if the mounts are too low because I must stock crawl and tilt my head down to line up with the hole. If the mounts are too high, I must raise up off my cheekweld to line up with the hole. Whichever mounts brings me closests to center, that is the mount I use.

Your lows may be the correct height for you and you'll then need to figure a way around the scope turret crowding the port. On the other hand, your lows may indeed be too low for you and crowding the port is unnecessary.

Food for thought,
Best

Just went through this battle with a Sako A7. Ended up having to go to high rings to fix the problem. I tried using a Leupold VXII in Medium rings, due the the turret caps on Leupies being a bit lower than most other scopes, but the brass still hit frequently. Moved to high rings, and the problem is finally solved. Since I was in high rings, I also switched scopes to a Monarch with a 50mm bell. I had tried moving a few different scopes as far forward as possible to keep the turret housing toward the front of the ejection port, but I was still having problems. The high rings was all I cold find to resolve it. This seems to be a common problem with A7's. I guess some rifles are just designed to eject brass on a higher arc than others.

IMO the problem is the fixed blade ejector at 6:00 and the extractor at 10:00, on a 3-lug bolt. This is also a common problem with Sako 85's. Going to a higher ring might help, might not. The blade is flipping the case up faster than the extractor can pull it sideways.

How high do you want to go to alleviate a design problem though?

The A7 does not have a standing ejector, it is a 75 push feed with an ejection plunger. The plunger is at 2:30 being slightly lower than the push feed extractor blade which is at about 10:00.

The 85 has an extractor blade that looks like a push feed, but it extracts the empty case like a Mauser. Take your 85 and chamber an emtpy case. When you slowly extract the empty from the chamber, the case stays straight with the chamber and flat against the bolt face. Gently draw it back until the case head just touches the 6:00 standing ejector. If you slowly pull it back against the the ejector, the case will initially tilt upward towards 12:00 until the case necks rises slightly above the edge of the port, but as you continue to pull back against the ejector, the grip of the extractor blade forces the case towards it's 10:00 position on the bolt face, which is the exact direction the case needs to go to clear between the scope tube and the edge of the port. Like any standing ejector, the force of the ejected empty is proportional to the force applied to the standing ejector as the bolt is drawn to the rear.

Based on my personal experience with 75s, A7s and 85s chambered in 243, 30-06, 9.3x62, and 375HH, the factory design does not work well with a crowded ejection port. If you prefer to stock crawl where you crank your face down requiring very low mounts to bring the scope down to your eye, you can run into problems, especially if you're using a scope with a bulky turret. The USMC at Quantico put an end to my old habit of stock crawlilng, and as a result, I find the ergonomics of the Sako design near perfect for a natural cheekweld where the sights are brought up to the eye. As such, the scope center does not need to be in the max low position and the ejection port does not need to be crowded.

Now this is based on my experience using the above noted standard chamberings. I have no personal experience with any of the shorter fat magnum chamberings which may have issues of their own.

Best

If a rifle will not eject fired cases with a scope mounted as I like it, I would sell it.

Any rifle with an ejection system that will not accomodate a properly mounted scope,regardless of ring height,is a flawed design IMHO.

Geezus for the money they charge for a Cooper or Sako, you'd think this stuff would be sorted out before the rifle hits the market.

+1.

Had the exact same problem with my Cooper Jackson Hunter in 25-06! Sent the gun back first time because of poor reliability on ejection. Got it back and it was hitting my cap just as yours, so I sent it back again. Neither time did they offer 2 pay for my shipping, which I should have demanded, but I just wanted my gun fixed before the up comming season. The gunsmith for Cooper sent a letter along with the rifle, stating that I was using 2 low of a mounting system, even though thier manual states 2 use the lowest mounting system possible, or something 2 that affect. I love the accuaracy and ergo's of this rifle but I was pretty angry that I had 2 shell out so much money, and have the problems that I had!

Send those guns back and make them fix them! Also tell them you want them 2 pay shipping!

HeavyBarrel

If you have a large windage turret on an X-Bolt short action this can happen as well.

Heavy - that is interesting. Was the letter from Mike H. at Cooper? Did you go with higher rings and did that solve the issue?

The brass seems to ding up both the bottom of the scope as well as the windage turret cap.

I agree with GaryVA in that the fixed ejector is in the wrong position. I have some older Sako's (L691 and AIII Classic) that are 2 locking lug rifles with the fixed ejector in the 8:00 position, and low scopes are no problem. When Sako went to a three locking lug design (75&85) they had to move the fixed ejector hence the problem with low scopes. I have an 85 Finn Light with Leupold QD bases and low rings with a Leupold VX 3 3.5X10 and it works OK if I eject the fired round with authority. I have no knowledge about Cooper rifles, except I would love to have one.

G2

My 85 has yet to be tested as a repeater. My engagements are one shot, one kill.

duckster, I was using Warne bases, with Leupold low rings. The first time I sent it back, it was not extracting reliable even without a scope, also had a burr somewhere that was making a mark on the brass. They did work on both problems so I thought I was good. Mounted scope with said ring/base, was extracting and didnt notice marks on windage cap until a week or so. I had mounted a brand new VX3, and while sitting in the deer stand admiring the gun, I noticed the marks on the turrent cap so after further investigation, I saw what was going on. Man was I mad! Got down out of stand and sent it back that day, I believe the letter stated that they re-timed extraction? I think the letter was from Mike. When I got the gun back, I ordered a low Talley aluminum ring/base, which is a little higher than what I had, seems 2 have fixed the problem. I insist on low rings, I like my cheek planted on the stock. If this had not fixed it, I would have sold gun, or kept sending it back!!

HeavtBarrel

Had the same problem with a Sako I bought on this board. Looking at the extractor I noticed the shell was popping off very easily. I had the gunsmith make a stronger extractor spring to hold the shell on a little longer. Just got a call from him that it works great now.

The 6 oclock position is not ideal but it must be able to work since so many people don't have problems with it. So by going off that fact, the upward ejection has to be a solvable issue. With mine, by the shell staying on the bolt that millisecond longer it was able to finish the "english" and tilt towards 2 oclock. If that hadn't worked I would have looked at the extractor shape and size, than the ejector.

I have sent a email to Mike H. at Cooper to ask him this same question that we are discussing. No reply as yet. Will be interested if this has happened to others besides HB and I?

duckster, please let us know what u find out.

Thanks
HeavyBarrel

Will do

Update:

I had this email back from Mike at Cooper:

"I have seen this as an issue with super low mounted scopes. Other than going with a different optics setup, there's not much we can do to keep the cases from hitting the windage turret, at least in current state of your rifle.

We do have a new ejection system we are going to in the M52. It is a plunger style ejector located in the bolt face, as opposed to the blade type you currently have. This new ejector provides for a more horizontal ejection path, as opposed to what you're experiencing. If you'd like, you can send your rifle in and we can fit a new style bolt to your rifle. The cost of this would be $200.

If you prefer not to replace the bolt, I'd suggest playing around with the height and location of your scope.

Mike"

So, I think I am going to try to raise the scope first and if that doesn't fix it, then go the new ejector route.