.416 isn't grouping well!

[Luvthunt]

I have a CZ 550 in 416 Rigby and use an RMR sight, gives me 3” groups at 75 yds. Believe it will do better after I get some trigger work. Trigger is really bad with creepy crawly issues. Plan on replacing.
First thing I would do is put your rifle on a bench with stable support and try that, no offense meant but would get a buddy to shoot a few groups to take the “me” out of the equation.
I have a Brno 458 Lott and the CZ 416 has a harder FELT recoil off the bench and the sticks.

 

[Opposite Pole]

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

I'm guessing recoil is the reason. Not a cartridge one would enjoy shooting of a bench.

 

[PHOENIX PHIL]

I'm the black sheep of this forum, I am not a Leopold fan, I have seen to many go down in the field.

First I would double check my rings. Just make sure the scope has not slipped in them. I have seen this happen a lot.

Look through the scope and adjust the turret. See if the crosshairs move at all, if it does, run it up 3-5 MOA and tap the side of the scope while looking through it. If it jumps or if the crosshairs did not travel with the turret adjustment. You easily found your problem. Send the scope off to be repaired.

Scopes have multiple lenses and if one comes loose it can cause you grief too, so as simply as it sounds. Shake the scope and make sure you don't hear anything rattling on the inside. If you do hear rattling, send off to be repaired.

I hope that helps you track your problem.

I'm with Inline on this. Leupolds aren't so tough they don't break on the big bores, they do. Leupold is fantastic at standing behind their product, but they do go down.

It's possible the load is the issue too, but like you I rarely see starting loads that bad.

 

[Graham Hunter]

I've shot the rifle at close range, 50 yards or so with the fitted iron sights. I did ok with it. Couple of inch group roughly. I'm not the best with iron sights.

The rifle is a CZ550 Aramid Composite with an aluminium bedding block. The stock is sound and the screws tight. I can't see any obvious damage to the muzzle. It's only fired around 20 rounds from new so I wouldn't expect fouling to that degree just yet. This is the only ammo I've used, but I will try upping the charge. None of the bullets keyholed, all made clean circles in the paper.

I think it most likely is the scope. Although it is a Leupold VX3, they're pretty tough!

A bullet doesn't have to keyhole to be unstable. With the load you are using you may not be getting consistent ignition/burning. But most likely it is your scope. Being a Leupold you get the best warranty in the business.

 

[postoak]

My 2 cents is to go back to the bench. Use a Led Sled if necessary to handle the recoil. Then lets us know what your groups are.

 

[Shootist43]

njc, it is a given that the 416 Rigby recoils a bit. It is very important to control the front end. My suggestion is to go back to the basics. Take off the scope and go to a bench using sand bags to support both the front and back ends of the rifle. I hold the front end of the rifle firmly in my hand and rest my hand on sandbags to steady it. The rear is supported by a sand bag again to help steady it. Iron sights are no big deal when used properly. Start off at 25 yards and see how your rifle groups, then move to 50 once you are satisfied. From there you can go to 100. Once you know how the rifle shoots add your scope. Use a FAT wrench to tighten all of the screws. Make sure your bases are specifically designed to be used on CZ(s).

 

[njc110381]

Thanks for all the replies guys. I'll take your ideas on board and work through them.

I suspect the scope is the issue but I don't have another one with the same tube diameter. I guess back to irons would be a foolproof way of checking, and also shooting from a bench. That isn't something I look forward to but will give it a go. The recoil is brisk but tolerable.

I took the rifle apart to work on the trigger. The factory unit is actually not bad when adjusted correctly but mine was like dragging a bag of rocks down a dirt road when I bought it. Absolutely awful! The sear adjustment was over two turns from breaking, it's supposed to be more like 1/4 turn. It was also heavy so I've brought it down to around 2.5lbs, about where I feel a decent field trigger should be. I removed the set function whilst in there. I then put it back together but not with a torque wrench. My friend has one, I'll borrow it and do it properly. Anyone know the specs?

The load is low but not too low. Charge range was I think 87-97gr in some manuals up to around 103gr in others. 90gr was at the low end but not silly, and the case fill is well within limits. I wouldn't expect a poor burn at that but will happily stand corrected. I'll chuck a bit more powder in and go again.

When it comes to scopes nothing is completely unbreakable. I like Leupold for their warranty, you can't fault that.

 

[fourfive8]

Well, the 416 Rigby is a cartridge designed around the very old temperature sensitive Cordite. That simply means most any low pressure, modern smokeless loads are going to be somewhat inefficient. Just part of the deal with a case of such volume.

As to the poor accuracy? Who knows, but I'd first make sure of mounts then check the scope. Try another scope and shoot from the bench. Use a sissy pad and get set up right. Not a thick soft pad but a large diameter fairly stiff pad like a double layer of heavy leather. Some soft, thick pads just give the butt room to get a "run" at your shoulder. Better to use a stiffer large diameter pad to increase surface area of butt. Make sure butt is firmly on shoulder but don't stiffen your whole body against the recoil. Be firm but give with the recoil.

Make sure of the mounts first then try a different scope and shoot carefully at 50 yds off the bench. You likely find out very quickly if it is the scope or mounts or (the worst case) something going on with the rifle.

 

[GeoffB]

I then put it back together but not with a torque wrench. My friend has one, I'll borrow it and do it properly. Anyone know the specs?

My gunsmith told me to try different torque setting to find a sweet spot once I have found a potential accurate load.
Front screw 50 to 60 inch pounds of torque
Rear screws 35 to 45 inch pounds
Start at the lower torque settings fire a group then adjust by 5 to 10 in Lb and shoot another group.
Loosen off and adjust to the new setting each time.
Its also worth starting low and torquing gradually each time you disassemble and re-assemble.
But I adjust by 10 in Lb at a time when doing this and swap between front and rear screw while torquing at each step.
I also use 222 grade Loctite (pink in colour) on the action screws on my two largest calibers.
This grade can be undone with hand tools. After hundreds of rounds and many hunting trips the action screws have never loosened up.
I only apply the Loctite once I have found the sweet spot. Apply sparingly (single droplet) on each screw.

I run both my .375 H&H and .416 at 60 in Lb on the front screw and 45 in Lb on the rear screw.
60 in Lb is the highest setting I have available on my wheeler torque wrench.
Both guns are epoxy pillar bedded as well.

 

[Inline6]

http://www.shooterstools.com/Pages/ATD/atdkits.html

Here is a better option for a toque wrench.

@geoff just check the specs on those actions screws 60 is getting up their. In a heavy recoiling rifle they have enough stress to deal with.

 

[gillettehunter]

Copper fouling can be an issue. I had a .300 WSM. Clean barrel it was a 1/2 inch gun at 100 yds. After about 10-12 rods the barrel copper fouled so bad the groups opened up to 3-4 inches. Clean it down to bare metal.
Next detail that can have an affect is bullet seating depth. Some bullets like to seated up into or close to the lands and others like to be seated deep. Usually big bores are not too sensitive to that.
I suspect like the others that the scope could be the problem. Next on my list is bases, rings, crown of barrel and then barrel fit in its channel. A number of things to check. Good luck.
Bruce

 

[mooze]

Just got back from the range and my first attempt at setting up my .416 Rigby scope. It didn't go well! I fired a three shot group of approximately ten inches at 100 yards and am now left wondering what could be wrong?

I'm loading 410gr Woodleigh soft points over 90gr of RL22. A start load. Recoil isn't too bad, I'm comfortable shooting the gun and was expecting much better. Shots were taken off of quad sticks - I can shoot a fox at 300m off of those same sticks with a lesser rifle...

Is it likely that variations in hold of the rifle could cause such inaccuracy or should I be looking elsewhere for answers? All my stock screws are tight, and the scope mounts too. I haven't looked too much further than that so far but I'm hoping it's something simple! If it's me then great, I can work on that and fix it. But I don't think I've ever shot a group that large with anything! I'm a little concerned.

I have the very same rifle but with the woodstock/Safari edition.
In terms of the stabilizing of the bullet: I have loads with 36 gr Trailboss at 1400 fps that stabilize the 400 gr Hornady just fine ( pest load), so your load should be ok. The twist is 1: 16.5
Woodleighs should be at least 2 mm of the land by COAL, may want to check that.
Rings were mentioned before: I have seen loads of self mounted CZ rings messed up: there is a designated back ring with a nose to fit into a notch on the receiver.. , very basic but worthwhile checking. Otherwise a really good system.
If it is not the scope, I'd check loose system screw and make sure the barrel is free floating.

 

[Shootist43]

njc, what torque specs are you referring to? Just the action screws or something else? My reference re. use of the FAT wrench was for the scope and base screws. The action screws are a whole different ball game dependent on many different factors.

 

[njc110381]

njc, what torque specs are you referring to? Just the action screws or something else? My reference re. use of the FAT wrench was for the scope and base screws. The action screws are a whole different ball game dependent on many different factors.

I was referring to the torque settings for the action screws. I've seen many rifles group considerably better when torqued to the correct figure and in the correct order. I just don't know what those figures are for a CZ550 Magnum. One thing I haven't done is check clearance of the barrel channel. The gun was shot with open sights and was doing ok pre trigger job but is now struggling, so it's worth checking. I've taken the gun apart since it was shooting well so could have done something wrong when putting it back together

 

[bruce moulds]

if adjusting torque on the action screws modifies grouping ability, there is a bedding problem.
same if it affects poi.
bruce.

 

[postoak]

Ah ha, you hadn't mentioned removing the action. That is no doubt your problem. Fixing it is the issue. I've been through this before and it is frustrating to have a great shooting rifle turn into a mediocre one because you removed the stock and reinstalled it. I had one Weatherby Vanguard that I found the front screw to be only finger tight from the factory but it shot great. When I put the stock back on I tightened to the factory spec of 35 inch pounds and the rifle accuracy went sour. I wound up setting the front at 10 inch pounds and the rear at 20 inch pounds but it never again shot quite as well as it did originally.

Factory torque recommendations run from 35 to 65, that I've seen -- I don't know what it is for the CZ.

Another issue is which order to tighten the screws in.

I doubt seriously that cleaning the bore or messing with the scope is going to do anything except waste your time.

 

[bruce moulds]

the problems referred to in this thread are highly unrelated to bedding.
it is either a scope problem, a scope mounting problem, or a bad barrel problem.
the inaccuracy described is serious.
factory bedding should in most cases give adequate hunting accuracy.
correct stress free bedding should improve hunting accuracy, but not the issue in question.
that said, barrel to forend contact would be well worth addressing, preferably by offering clearance.
problem with this is that it could void warranty.
bruce.

 

[postoak]

Bruce, how do you explain his rifle shooting so well before he removed the stock from the action?

 

[bruce moulds]

how well did it shoot before?
bruce.

 

[postoak]

I reread the thread. It sounds like he changed two things -- switching from iron sights to a scope, and removing the stock and reinstalling it. I would try to eliminate one of those changes by going back to iron sights and shooting off the bench to see where he is.