I am sighting in my new 7mm-08 Mossberg Patriot rifle for 200 yard zero. The scope is Sightron Big Sky 3x9 with hunter dot reticule. The trouble is erratic fliers with lighter bullets. I am firing 5 shot groups at 200 yards with 120 gr Sierra prohunter and 139 Hornady interbond bullets with unacceptable results.
I have hunting accuracy of 2.5 to 3" groups at 200 yards with Hornady 154gr SST bullets over imr4064. I prefer 120 or 140 weight bullets for deer.
Problem is with the lighter weight bullets. 3 or 4 shots are within 2 inches but there is always 1 or 2 fliers 3 to 4 inches from the group. The fliers are usually horizontal in nature. The barrel is completely free floated and all bolts and screws are tight. It is 20" bbl and does heat up. The 120 Sierra prohunters over imr4064 or h380 are averaging 6 inch groups for 5 shots. The groups with Hornady 139 interbond bullets average 5" for 5 shots at 200 yards.
Your thoughts?
Don't bother with adverse comments about Mossberg. I really like the feel of this new rifle with wood stock.

I don't know anyone here who likes Mossberg centerfire rifles. However, I've seen Vortex scopes that are chit, right from the get go. Here's a list I tend to check when looking for a good consistent shooting rifle:

1. Is it properly glass bedded?
2. Are you using a "proven" scope.
3. Scope mounts and rings secure and loc-tited. Screws aren't too long to cause issues.
4. Mag box isn't binding up.
5. Both locking lugs in contact.
6. Good clean trigger with appropriate pull wt.


These are just basic mechanicals I look for, not including bore condition, chamber condition, crown, and proper twist rate for bullet you are using.

If you are getting horizontal "flyers", it sounds like your barreled action is skating around in the stock or maybe the scope is garbage. Chances are, it's both..

I tried the interbonds in four different rifles and couldn't get them to shoot. I have never tried the 120 prohunters. I shoot the 130 Speers and 140 sierras.

Bedding? Not familiar with that gun, is it supposed to be a sub-moa shooter?

The Patriots have developed a reputation for being shooters. I'd be inclined to find a spare scope to see if the problem persists.

Are you getting parallax at 200 yards with your scope?

I will switch scopes next week and see what changes.

You checking your rounds for run out? I'd try a 140 ballistic tip, and/or different brass. I've had three 7.08s, and all liked the 140 and varget and r15.

Varget

I've been working with a Kimber 84 and had some difficulty. I discovered the action screws were not tight. You might go through the whole system: Action screws, base screws, ring screws.

Ramshot Big Game is also very good in the 7mm-08

Sure is.









Good luck finding it.




P

Sounds to me like your rifle doesn't care for the bullets you want it to shoot. 154 Hornady's will surely kill deer at 200 yds. Seems one of the 2 of you has to decide whether to spend $ to get it going your way or to keep monkeying with it or sending it down the line.

Find some 140 grain Partitions.

Put 42 grains of Varget in a case sparked by a WLR primer.

Make the OAL 2.805.

Shoot tiny groups.




P

My go to 7-08 load for all mine is 140 gr Ballistic Tips with Reloader 19. Never seen a 7-08 that didn't like that combo.

My first guess, though would be your Sightron scope. Spend $200 bucks for a Leupold VX-1 and throw that POS away. Thank me later.

I'll take a Sightron Big Sky any day over a Leupold VX 1, 2, or 3...

Hotrodder...grin....

No worries, recently a Ramshot CSR assured me by email that they are, I'm paraphrasing here, not full of chit and more is on the way.... LOL

I'll believe when I see it.

I'm south of you a bit but I'll keep an eye out for you if you'll do the same. Big Game and Hunter.




P

You betcha. I don't really plan to use their stuff though. Looking out for Varget here. Cheers.

I see Varget regularly.

Guncrafter's in Salem had several pounds last week.





P

just post it in the classifieds and make some money

Yup. Totally agree. Very under appreciated optics IMO.

Varget is my go to powder.

Accuracy problem solved. I switched to a Minox 3x9 scope and hunting accuracy is back. Groups ran 2 1/4" using imr4064 and 154 sst reloads.
Accuracy improved with H380 powder and the new scope. 43 gr of h380 pushing 154 sst grouped 1.05 and 1.33. I accept that for this Mossberg timber hunting rifle

So not sure if it was scope or new powder?

Your shots must be close...

Good luck!

Try a box of Barnes 120gr TTSX factory. They shoot so good in my Sako 708 that I don't bother reloading.

I like 4064 with 7x57

Glad you got things worked out.

Big Game is da bomb with 120's; I've been hoarding my last pound. Good to hear it's inbound. Now if WW will just actually do that run of 7 WSM brass they teased us with...

OP: you are describing my first 7-08 to a "T". It'd do ok with heavy bullets (150's in my case) but throw horizontal flyers big time with anything lighter. Exhausted the usual suspects, finally just rebarreled it.

I got 16 pounds of each last week (I already had a jug of each).





Big Game is the only powder I use for my 7mm-08s.






P

Pharmseller, now that would be worth the drive to Oregon

I reload and cant really stand factory ammo BUT when I purchase a new or new-to-me firearm:

I clean it (new rifles get a breakin period)
mount a scope I know is fine
Finally I shot a quality box of factory ammo
There are certain lines of ammo I won't shoot. Once you've figured out the issue, start loading cause now I'll have a whole new set of issues to deal with:
Powder
Charge
Primer
Bullet
Seating depth
What is a tack driver in one rifle might not be so in another one.

I'd bet $10 to your dime that 42-43gr of Varget & a 140BT will get you into DRT territory real quick, provided you have absolute confidence in the scope. I'm Leupold 100% though.

Primers and seating depth are the next two steps.

Good shooting.