Weatherby Mark V Ultralite Accuracy

[Greek54]

Hi. I am an intermittent post at best. However, once in a while I have a question, so here goes. I have a Weatherby Mark 5, Ultralite in 7MM Remington Mag. I cannot get it to shoot better than about 2&1/2 inch groups at 100 with a anything at 160 grains or above. It is a 1 in 10 twist would like to get some suggestions. Should I sell it, try to have it accurized or re-barreled? Thanks for the help.

 

[Dr. Vette]

I suspect it has more to do with what that particular barrel "likes" than anything else. I tried several 160/168 weight bullets in Dad's 7mm Wby with no success. I then went to the 150 Barnes TTSX and it shoots tiny little groups.

Has anything been done to your rifle at all?

 

[MudRunner2005]

Hi. I am an intermittent post at best. However, once in a while I have a question, so here goes. I have a Weatherby Mark 5, Ultralite in 7MM Remington Mag. I cannot get it to shoot better than about 2&1/2 inch groups at 100 with a anything at 160 grains or above. It is a 1 in 10 twist would like to get some suggestions. Should I sell it, try to have it accurized or re-barreled? Thanks for the help.

I had one of "those" Weatherbys... I recommend before you go through all the money and headaches I did trying to find accuracy of a lost cause... Have the barrel professionally borescoped. You probably have a junk bore. My Accumark was defective from the factory...Weatherby wasn't any help. Traded it off, lost a bunch of money, and got something else. Lesson learned.

If I were you, I'd sell it or rebarrel it.

 

[toddc]

Stability over 160 gr with a 10 twist could be a crapshoot. The Berger 168 at 3k at 2000 ft is 1.47 SG which SHOULD work but who knows in whatever particular barrel. Try some 140s and see. If they also suck you might check the usual suspects, scope, mounts, rings, barrel and bedding.

 

[toddc]

I had one of "those" Weatherbys... I recommend before you go through all the money and headaches I did trying to find accuracy of a lost cause... Have the barrel professionally borescoped. You probably have a junk bore. My Accumark was defective from the factory...Weatherby wasn't any help. Traded it off, lost a bunch of money, and got something else. Lesson learned.

If I were you, I'd sell it or rebarrel it.

Amount of jump could also be problematic with many longer designs. You could be .2 or further off the lands seated to neck juncture.

 

[MudRunner2005]

Amount of jump could also be problematic with many longer designs. You could be .2 or further off the lands seated to neck juncture.

I had to literally beat a cleaning rod out of the bore with a wet patch and jag on it with my hand, towards the end of my battles with this rifle... The bore was caving-in the more I shot it, and didn't' realize it. The jump was not the problem. I went to the smith and had it scoped...The bore was caving in and trashed from a defective factory barrel (Criterion).

 

[MudRunner2005]

Stability over 160 gr with a 10 twist could be a crapshoot. The Berger 168 at 3k at 2000 ft is 1.47 SG which SHOULD work but who knows in whatever particular barrel. Try some 140s and see. If they also suck you might check the usual suspects, scope, mounts, rings, barrel and bedding.

My Browning A-Bolt II 7mmRM had a 10" twist factory barrel... It would shoot the 168 VLD's, but nothing heavier... 180's (even the Hybrids) patterned like buckshot at 100. Now it wears a modified 26" Remington 700 9.25" twist sporter barrel (I built it back in 2014, I call it the "Brownington" ), and shoots 1/2-3/4 MOA, usually closer to 1/2-5/8 MOA.

 

[Deleted member 46119]

Follow the suggestions on diagnosing the issues. I'll add:
Check the action screws torque.
Scope mounting is tight.
Chamber and neck area of the chamber are clean.

I'm big on Mark Vs. I have .... (mumbles something incomprehensible because embarrassed by how many Mark Vs) or more.

My 7mm is a 7mm Weatherby not 7mm Remington Magnum.

Lighter and faster works in Weatherbys for me.

If it were me:
Try Barnes 145 LRX or 150 TTSX using IMR7828. Weatherbys like 7828 http://www.barnesbullets.com/files/2016/03/7mmRemingtonMagnumV10ForWeb.pdf
Lots of 7mm bullets are terrible when testing at 100 yards. Try to test at 200 or 300
If using copper jacketed I would use Nosler as Weatherby has had a good relationship with Nosler for a long time. Specifically the Accubond LR 168.
When you think you are going fast, go faster (be safe of course)
Lighten up the trigger.

 

[Deleted member 46119]

If it were me, I'd give the Barnes 120 TTSX a go as well.

Weatherbys like fast. 3350 should be easy with IMR7828SSC. Other powders can do it. Reloader 26.

"Flat" to ~400 years and plenty of power at that range.

 

[Greek54]

Thanks for all the suggestions. I have tried all the standard accuracy issue fixes, bedding screw torque; scope mounts (I have a Swarovski on it with Talley mounts-all tight); tried working up loads and experimented wth bullet seating depth. All no go.

I have not tried bullets weighing less that 160 grains, as this was to be my elk riffle. I will give the 140's a try, though.

It sounds like some have had good success with rebarreling. Any suggestions as to barrel maker and a gunsmith that works on Weatherby's?

Thanks again for all the good thoughts.

 

[Rich Coyle]

Greek54,

Some rifles prefer specific bullets. I had a 7mm Weatherby, not the 7mm Rem, in a Mark V. With Nosler 150 Ballistic Tips I could put five under an inch. With my home made 140 grainers I could put five in 1/2". It loved the original Barnes X 140s. They ran three shots about 5/8".

I suggest you switch to a lighter bullets.

 

[Deleted member 46119]

...as this was to be my elk riffle. I will give the 140's a try, though...

A TTSX going ~3150fps should be good to ~400 yards on elk. Again, faster is better.

If it is your only rifle in this class, no reason not to use it.

I have to add just because I like them. You could rechamber it to 28-Nosler. Then it will go really really fast. Hehehe.

 

[Dr. Vette]

I have not tried bullets weighing less that 160 grains, as this was to be my elk riffle. I will give the 140's a try, though.

I can tell you that the 150 TTSX with 75.0gr of H-1000 will work exceedingly well on elk.

 

[Rich Coyle]

If I was using TTSX I would use the LRX bullet. I would choose it because it opens faster and still plows though.