.416 isn't grouping well!

[Tokoloshe Safaris]

You really posted some good info. I have one CZ 550 .375 H&H Swarovski Z1 scope Bell & Carson stock, very accurate and reliable. I never thought about hitting the butt against the ground to seat the barreled action. Action screws came loose once after proper tightening, it had never happened before or since. That must have been the cause.

For whatever it is worth I am a firm believer in stand up shooting benches with hard recoiling rifles. Maybe not quite as stable as a sit down, but it sure lessons the recoil while providing a reasonable stable shooting platform and possibly preventing a irreversible flinch!

Thank You

 

[njc110381]

I had a quick look over the gun yesterday. No signs of the scope slipping and the rings were nice and tight. The action screws were a bit slack so I wonder if that could have caused the issue? I've tightened them up and will test fire before taking the scope off. I'll take tools to the range to work on the gun if needed.

 

[Ridgewalker]

Scope movement, this is how I watch for it. I put painter’s tape next to the rings after installing a scope and watch to see if it is getting crunched for a few trips to the range. After it proves good, I remove it. JME

 

[Bullthrower338]

@One Day... did you use the friction tape that is supplied with the AA rings? I also found them to be extremely well machined

 

[One Day...]

No signs of the scope slipping and the rings were nice and tight. The action screws were a bit slack so I wonder if that could have caused the issue? I've tightened them up and will test fire before taking the scope off. I'll take tools to the range to work on the gun if needed.

I would think that action screws "a bit slack" are unlikely to produce the kind of results (10" spread) you refer, unless of course the barreled action is rattling inside the stock, which is likely not what you are describing... Scope sliding is insidious, it will not move 1 mm (1/16") at a time, and for movement visible to the naked eye to happen, you will likely need to shoot several dozen rounds... Hence the value of putting some sort of marker on it...

Scope movement, this is how I watch for it. I put painter’s tape next to the rings after installing a scope and watch to see if it is getting crunched for a few trips to the range. After it proves good, I remove it. JME

That ought to work well too. Never tried. I like two spots of nail polish on the front and rear edges of the ring, straddling the ring and scope tube, because even if they do not completely crack open (big move) they have zero elasticity and even the slightest movement of the scope will create a stress crack clearly visible to naked younger eyes or magnified older eyes

@One Day... did you use the friction tape that is supplied with the AA rings? I also found them to be extremely well machined

No I did not and this may be the root cause of the rings closing without discernible gap. Obviously, the thickness of the friction paper is subtracted from the equation and from this perspective your assertion that my scope was improperly mounted can be logical.

An "experience" with friction paper...

But there is a reason why I did not use the paper. I have another "experience" with friction paper... Allow me to clarify that I use the word "experience" not in the meaning "expertise" but in the meaning "it happened to me" .

This "experience" is the following: a while back (15? 20? years ago) I was hunting deer in Pennsylvania, during the 1 week season (week after Thanksgiving) and we had constant rain/sleet/snow for several days. I was using a rifle with the scope mounted using friction paper. That rifle, after thorough drying, cleaning, lubing, etc. went back to the safe, and as was fairly common for me in those days, I did not re-use the rifle for a couple years. I was in gun buying madness those days and was consistently getting a few new rifles every year... A few years later, can't remember how many, when that rifle came out of the safe (the safe included a dehumidifier so called, what was it? "Golden Rod"? essentially a small electric resistance in a tube) I was flabbergasted to realize that there was a crown of rust all around the rings. Taking the dang thing apart, I realized that the friction paper has obviously soaked up water during that inclement weather hunt, then released it progressively and caused both the rings and the scope (1980's era steel tube Swarovski) to rust deeply enough that both rings and scope tube were pitted... That is the last time I used friction paper to mount or re-mount a scope... Obviously, there are not many steel tube scopes produced anymore (but plenty of vintage ones), but most of the rings are still steel, hence it can still happen

Generally scope rings are designed to have a small gap when tightened up, so the thickness of the friction paper is not required (even though its friction characteristics may still be desirable) but maybe the Alaska Arms rings are machined closely enough that the thickness of the paper is needed. I do not know...

This being said, I have been shooting hard recoiling rifles since the 1990's (that would be about 30 years now - I remember ordering .458 Lott ammo from Art Alphin at A Square when it was announced, the first commercially produced ammo for the Lott, and waiting a couple months because the production was not started yet) and I have been around quite a few big boomers being shot. In those days, .416 Taylor, .450 Watts, "souped-up" .458 Win, .458 Lott, the occasional rarissime vintage .416 Rigby with folks turning the belt off .460 Wby cases to make .416 Rigby cases, plus a decent number of .460 Wby, .378 Wby, or still in those days .375 Wby etc. My recollection is that scope sliding issues were constant! People tried everything: bondo goop, friction paper, rings so tight as to indent the scopes, Loctite, roughing the inside surfaces of the rings, etc. etc. you name it! The only things that really worked were European rail-scope with mounts secured by cross drilling the rail, or what I described: simply resting the rear ocular shoulder upon the rear ring. Admittedly scopes were generally heavier then than now, hence they had more momentum to move forward under recoil.
All of this to say that scope movement issues on heavy recoil rifles is nothing new

The other challenge of course was securing the bases to the action, and the common fix (that worked) was to re-drill and tap the 6-48 threads and replace the factory screws with 8-40 screws, generously dipped in red Loctite. By the way, the presence of built-in scope bases on the CZ, is one of the reasons why I prefer it over the old (and new) CRF Winchester 70. You can easily retrofit a true firing pin-blocking, bolt-mounted Win 70 type safety on a CZ (ZKK in those days), but you can hardly machine scope bases on the action of a Win 70...

 

[One Day...]

Hello njc110381.
It has been a while. How goes the battle?
Thx
P

 

[njc110381]

Hello njc110381.
It has been a while. How goes the battle?
Thx
P

No progress yet. I missed the last range day because I was away on holiday. Hoping to take a look at it at the end of this month.

One weird thing I did pick up when messing with the rifle, the magazine holds four rounds? I thought it should only take three?

 

[One Day...]

Actually, the wood stock version holds 3, which is what creates the general expectation because it is what is published, but the Bell & Carlson stock (a.k.a. factory "aramid" stock) has a slightly deeper belly and it accommodates a 4th one This is one of the advantages of using that stock. I thought I mentioned it along the way, but it may have been in a different thread

 

[Ridgewalker]

One Day... I like your clear fingernail polish method and plan to try it the next scope change I do. It can be left on permanently. At the range, guys are always asking me why the tape is on my scopes. The polish should eliminate the looks and questions I get.

 

[bassasdaindia]

Are you loading more than 1 bullet in the magazine of the rifle at a time or are you placing 1 into the chamber and then firing it ?

 

[IvW]

What primers are you using?
What is the load density?
What is the velocity over a chronograph?

Back to basics.

Buy a box of factory loaded ammo, take the scope off and shoot it at 25 and 50 yards off the bench and see what happens.

You could also ask somebody who is use to shooting a bigger bore rifle to do half the shooting to have a comparison.

You would then be able to eliminate a few issues or pinpoint a few others...problem solving is a process of elimination.

 

[Nhoro]

Back to basics.

... off the bench and see what happens.

Good advice... see if you can get a lead sled and shoot off the bench. Let the barrel cool between shots. Then you know it is the gun performance.

 

[bruce moulds]

or shoot at 1oo on an appropriate sized aiming mark for the sight.
if it won't shoot at 100, who wants it anyway.
if it looks good at 25, it might still be crap.
bruce.

 

[Dr Ray]

Just curious why you are doing load development off of sticks and not a bench with rests?

Exactly.
I think that’s the problem.

 

[Hogpatrol]

I don't hunt DG but if it were the case I'd use the same rifle qualifications that I use for all other game. Where does the first bullet out of a cold dirty barrel go? One may fire multiple shots and need to have a good group but that first shot is what counts. For load development, use good, solid rests, not some floppy sandbag or wobbly lead sled / one piece setup, shoot one or two foulers, wait until barrel cools to ambient temperature, consider the next one the first shot, wait until barrel cools to ambient, fire another, repeat this process until a satisfactory load is achieved. Hunt in confidence.

 

[njc110381]

I must have overlooked being told about the Aramid stock holding an extra round. All the more reason to have it, although CZ still list 3 shot capacity on their website which is odd. That's a major selling point!

I've loaded the rifle in various ways. I always put the round in the magazine so it feeds smoothly under the extractor but I may load one, two or three. That said I have checked the rounds. The bullets aren't shifting under recoil so it shouldn't make a difference. It's not being fired fast enough to get hot, although it does warm up a little. Not enough that it would shift shots that far. An inch or so maybe, but not six!

Primers are CCI Magnum. Load density is approximately 90%. Velocity is unknown but will be somewhere about the 2200fps area going by book data. It shot that badly that I didn't make much effort to find out finer details. I'm reluctant to buy factory ammunition for now as I can home load a round that should be considerably better than this. I've never had a rifle group this badly and I've had at a guess 20 rifles and have probably fired 20,000 home loads in my time shooting. If I get a three inch group at 100m it's a crisis, this is on a whole new level!

I am planning to get a chap I know to shoot it for me if I don't solve the issue fairly quickly but intend to chase the basics myself before bothering him. He's a firearms trainer with experience of big bores. If he can't shoot it well, nobody can. My shooting off of sticks could be an issue due to the recoil, but I can shoot a smaller calibre into 1" or so at 100m that way. I find it hard to believe it's my technique that's stopping me from getting anything even resembling a group, even though the rifle kicks hard?!

Would the solid rest be considered vital for all load testing or just for big bores? Reason I ask is because off of a bag I can put five rounds into a ragged hole with my .22-250 or 6.5x55 when the loads are right for the rifle. I'm really struggling to see how it can be quite this bad without something else being the issue? Pilot error may open the groups a bit but not this much surely?!

 

[Shootist43]

Njc, for load development purposes, I generally use more solid rests. Once your load is established, shooting it offhand or off sticks is what you need to practice for hunting. I haven't tried the "quad" sticks" but in theory they should be very stable. Go to Nathan Foster's website, then to a section called the "knowledgebase" from there go to an article entitled Hold that Forend , https://www.ballisticstudies.com/Knowledgebase/Hold+that+Forend.html

Not controlling the front end of a big bore is probably the quickest way I know of, other than flinching to shoot a poor group.

 

[TTundra]

I find it hard to believe it's my technique that's stopping me from getting anything even resembling a group, even though the rifle kicks hard?!

I was an experienced shooter when I began with big bores...but it was a whole new world of learning and I was humbled very quickly.

Like @IvW said, back to basics at 25 and 50 yards and get a chronograph. We've all been there in a stump and had to go back to crawl to get running again.

 

[IvW]

Try Federal 215 magnum primers...

 

[One Day...]

Seems to be a sudden rejuvenation of the thread with a number of repeats from previous posts. All good

I will not repeat myself, what I said is still available in the thread, but it may be worth summarizing.

1- If you are dealing with 6" to 10" point of impact shifts at 100 yd, and if you have a decent experience reloading - which you apparently have - the issue is not your ammo. Period. Issues of primers, powders, load density, etc. will simply not cause this type of dispersion.

2- For this type of dispersion to happen, something mechanical is moving. Period. From there it is rather simple:
a- it can be the barreled action rattling in the stock. Already checked out.
b- it can be the scope sliding in the rings. No answer so far on that point. To be checked...
c- it can be the entire scoped rifle dancing on your arms under recoil. Relatively unlikely given your shooting experience, but definitely worth checking. Big bores DO change the recoil control equation.

Take the detachable rings off to eliminate the scope/rings from the equation and have your expert friend shoot the rifle. I bet you that with iron sights he keeps it inside of 3" at 100 yd with your basic load. I further bet you that YOU keep it inside of 4" at 100 yd. These big bores CZ are pretty dang reliable and accurate, and they have ALL been shot at the factory (you should have that target with your rifle).

That will prove that the rifle and the load shoot.

Then you can start exploring these tips (see posts on p. 3) about your scope moving in its rings and where to locate the front ring on the front bridge

Do not be overly worried and do not get yourself too deep in the weeds at this stage, you are not chasing 1/4 MOA but 6 to 10 MOA... NO new rifle shoots that bad, and it is not exactly like you are the first guy with the problem on a brand new scoped big bore