SNAFU.....Rifle? Scope? Load ? less than3 weeks to resolve

[284allways]

Gents.
I am knee deep in the swamp..
I have a 300 wtby with a muzzle break ...a reputable build ..Jarrett
I have had a VX3 3-10 and due to what Leupold thinks is a broken scope ...
>>I have replaced it with a new VX3I
I was loading Swift Scirocco 180's with 84.6 gr of 7828 to 3,225 fps (weatherby brass and fed 215's) All on Redding dies and comp seater die. Blew out a SAKO extractor and developed ejector marks on the brass, stopped that !!
Full prep on the brass ..no neck turning-
Swift only reccomends 81 gr of 7828???
>>Swapped to 180 gr AB with 84.2 of 7828
I am using talley vertically split rings.
My bech gear is a Sinclair bench rest, a NULA bench wizzard and a supporting bag under the butt stock behind the pistol grip. Shooting at 100 yds & 200 yds
I think the gear is fine and my form is good

1st issue ..cant keep the top screws or bottom screws tight in the scope rings ...should I use a tread locker. This seems to be taboo??? They loosen about 1/4 turn every dozen shots ?
2nd issue My groups are about 5/8 (3 shots)on a good day at 100 but when they are not the PATTERN is 2 at POI and 1 and 1-1/4 low
3rd issue ...200 yds the PATTERN is now like above by 2x in size ....

The action is bedded solid and action screws are per mfg spec..
New scope tracks (ajustments are good)
Ammoseems sound now .. no pressure
will i get the deviation in group sizes from loose ring screws ?

Thoughts? I think i am too close to the rifle/load now to see clearly

 

[SJB358]

First off, I would def put some threadlocker on the screws if they are loosening up. It's alot of recoil even with the brake.

I would put a known good scope on the gun and shoot it. I just destroyed a 6X36 Leupold this weekend on a 300 Weatherby myself.. Well, I shouldn't get ahead of myself, the gun shot fine in the past, not much has changed except for the scope..

Wish you luck sorting it out, but I would cement the fasteners and use a known good scope and see what happens. If screws are backing out it is affecting the groups before they are noticeably loose.

 

[Dr. Vette]

What torque are you using when you using on the rings?

Personally, I am not a fan of the Talley vertically split rings. Their lightweight alloy mounts are great, but there is too much room for error with the vertical ones.

I have or work on several Weatherbys including a 300 with a brake, and never use thread fastener with no problems so far. However, I use a FAT wrench to torque every fastener.

 

[mjcmichigan]

Blue thread locker, not red.

Make sure they are torqued corrected...

From memory 17-20 ft #.


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[JD338]

I just went through the same thing on my M700 LSS 338 RUM and a VX-6 3-18x44mm.
Here's what I did and it's working.
-Replaced scope, VX-6HD 3-18x50mm. Revamped turret system.
-Reset action screws at 35 in lbs. They were at 55 in lbs
-Deep clean barrel with Sweets 7.62 and JB Bore Paste
I've got her back on track.

JD338

 

[truck driver]

Not a fan of vertical split rings since you can't get the tension right to hold the scope firm.
But I am a fan of Tally light weights and would prefer them over the twp piece base and ring type.
If you don't have the time to replace the rings and bases then blue loctite them.
In your case I think it's the torque caused by the bullet traversing the barrel that is loosening your rings not recoil.
The Swift Sirocco II are known to produce high pressure do to the jacket metal and baring space. I think we all have seen Swift Sirocco's spike some pressure.
If you want to use them just back the powder charge off to Swifts recommendation and if no pressure signs work up to where you want to be.

 

[RL338]

As already stated quick fix would be blue Lock-tite. I would guess you are using a radius style vs side ported brake. I have found my Accubrakes on my Weatherbys tend to vibrate the rifle more so than my side port brake rifles.

 

[Guy Miner]

"3rd issue ...200 yds the PATTERN is now like above by 2x in size ...."

Yes, at 200 yards the group/pattern is normally about twice the size of the group at 100 yards. Geometry. It will continue to get bigger as ranges increase. Your 5/8" three-shot group at 100 yards is commendable and a great indicator that your rifle, scope and ammo are capable of some seriously good accuracy. Nice!

I don't know why you're getting two impacts at point of aim and one low. Time to check everything, one piece at a time.

Non-hardening thread locker. Yes! clean the threads first, then non-hardening thread locker. Works great.

Did you carefully work up to these loads? They're pretty warm, close to max? Ya, I know, that's what a 300 Weatherby is for! I see Nosler shows a max load and most accurate load at 84.5, so you should be good with your slightly lower load. Should. Sometimes the most accurate load for a given rifle though, is below max.

Last year I settled for a mere 2600 fps from a 200 gr Nosler Partition, using my 30-06 even though I believe I could have seen a good 100 fps more. The load was not only accurate, it was shooting so doggone well... Mild, smooth recoil, easy extraction. I really loved it when I got to that 2600 fps level. It worked just fine on the range and in the field. I still like it, and was very tempted to use it again this year although it's considerably slower than my normal 165 gr 30-06 load.

Guess what I'm trying to say, is that happiness isn't always found at max or near max levels.

Nice methodical approach should yield improvements. I like JD 338's description of what all he did to get his big-boomer shooting well again.

What are you hunting with this mighty Jarrett?

Best of luck to you! And do you have an alternate rifle ready & available, just in case?

Regards, Guy

 

[Nimrod84]

I'm with TD, Dr. Vette, JD338, Guy Miner, etc.

Scirocco's are long bullets with lots of surface area and the jacket material tends to drag rather than slide over barrel. As such pressure will be higher with them compared to many other bullets when using the same powder charge.

Light weight / aluminum split ring scopes are notorious for not holding on large bore guns. Vibrations from a large powder charge can and do cause them a lot of problems even if there is little felt recoil. Removable blue locktite / threadlocker is your friend, nail polish can be used as well on the outside (over the threaded portion of the screws and a dab or two where the scope and rings meet) and the polish will crack or break allowing you to see if the screws have come loose or the scope has shifted.

Your 2nd issue could be related to the scope screws; but I think your load could be on the edge of an accuracy node and as such it is temperature sensitive. After addressing the scope mount (replacement or thread-locker) I would consider dropping the powder charge a little for 5-10 rounds to see if the POI issue resolves it self or gets worse. You can also watch the bullet velocity to see where it levels out. The goal is to find areas where moderate changes in powder weights don't affect velocity very much; that means that some temperature or charge weight variations won't readily show up on the target. Others can explain the concept of a "node" better than me.

 

[rodell]

Definitely a good cleaning is in order, just to be sure. For the rings, use a torque wrench. (And that's in-lbs, not ft-lbs!)

If they won't hold at torque, you'll have to lock them. I've never had to once set at the correct value. If you do, I might consider changing the mount - there's no reason they shouldn't stay tight unless they are REALLY greasy once torqued down. If the scope is loose, anything is possible.

Check with the manufacturer on the correct torque for the action screws. It's 55 in-lbs for Weatherby rifles, 35 for Remington 7000's, if memory serves. Obviously a wide variation.

 

[mjcmichigan]

.....(And that's in-lbs, not ft-lbs!)

....

Thanks for clarifying!


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[284allways]

I appreciate all of your wisdom! Thank you.
After 40 years of being a shooter I dont own a torque wrench.....go figure ! I will pick one up.
I have applied "blue"to the bottom and top screws. I have the Talley vertical rings on several other rifles and dont have this issue.

I will try the rifle and loads again after loctiteing. I will take the next step and reduce powder and give it a try. Velocity is nice but I feel no need to push the rifle.

I do have a back up rifle, and I will be chasing elk and muledeer, the opening day is one month a way !

Thanks again for your direction and things to ponder/consider.

 

[BretN]

Sounds like you're well on your way to having it sorted out. If for some reason the problem persists, there's no shame in using an old tried and true rifle and load. I've had to do that myself when one of the guns I wanted to hunt with wasn't cooperating. Bring both guns to the range next time to give them both a good run through. Good luck with your hunt.

 

[IdahoCTD]

If your going to do some load work I would try some H1000 too. When I was shooting my 30-8mm (a regular shouldered 300 Weatherby) R-22, 7828, and H1000 they all shot about about the same group wise but H1000 is much more temp stable then the other 2. Quickloads says 7828 is quite a bit faster but I never experienced that. They all shot within 50fps of each other. 7828 loads were 1gr more that R-22 and 4grs less than H1000 in most all of my loads. BTW a 300 Weatherby has almost the exact same capacity as a 30 Nosler.

I would run a ladder test and then play with seating depths, as much as your throat/mag length will allow. In a relatively short order you should see something shine. It sounds like you have other issues with the rifle besides loads though. I just had a VX6 crap the bed too. I've had extremely good luck with Leupolds over the 30 years or so I've owned them but my luck ran out last week.

 

[Anonymous]

Something is goofy with those mounts...I've never had rings shoot loose.

If you break it down, I'd be sorely tempted to stick somthing else on there. I really like Warne Maximas on the hard kickers.

I'd also probably de-copper the barrel. If you blew an extractor...you were getting some serious pressure and as mentioned the Scirroco has loads of bearing surface

 

[SJB358]

Something is goofy with those mounts...I've never had rings shoot loose.

If you break it down, I'd be sorely tempted to stick somthing else on there. I really like Warne Maximas on the hard kickers.

I'd also probably de-copper the barrel. If you blew an extractor...you were getting some serious pressure and as mentioned the Scirroco has loads of bearing surface

So I’m using the 180 Scirocco with 7828 in my 300 Weatherby as well. About the most speed I could coax was about 3150 before I started seeing ejector marks. Likely about 3100 is where the load will be. Maybe not the classic 3200 of the Weatherby, 3100 doesn’t leave much out there either.

 

[DrMike]

3100 fps is still a velocity that will impress game when a 180 grain Scirocco hits home.

 

[Wyo7200]

One thing you can do is use a .5mm pencil to trace where your scope rings meet the scope and add a little tic mark going from the ring to the scope so you can tell when your scope starts to walk out of the rings while shooting.


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[JD338]

I would change to a picatinny base and steel rings.

JD338

 

[hunter24605]

I had that issue with my 325 wsm, two of the screws were notorious for working loose over time. I gave them a dose of blue loctite and the problem went away. I've since replaced the rings and the blue loctite was easily removed...When you get your torque driver, give the action screws a look, loose or over/under torqued action screws could be your culprit..It caused me to do a lot of head scratching when my brothers rifle suddenly developed erratic groups. After checking scope, rings, and ammo to no avail, I checked the action screws and one was indeed a little loose, but BOTH needed torqued to the proper torque values. After torquing them the rifle started grouping again.