What kind of accuracy should we look for in a 338 semi custom build?

[WildBillG]

I just built a 338 RUM on a Weatherby Mk V action it has a Jury barrel 1 in 9.35 twist. Bob Jury is well known in Alberta for making great barrels. I don't have 50 rounds through this rifle yet and it has given me a .434 3 shot group with Sierra 250 GK. Today while looking for a load with 300 grn Elite Hunters it gave me .618 3 shot group with RL 33 at 96.0 grains. The Sierra group was using RL 25 at middle of the road Nosler data. I am using Bertram brass. I want to use Fed 215 M primers but they don't fit in all of my brass they are to big.
Any way should I be super happy with these groups or are the big 338s capable of even better. I still have a ways to go to get to max load I believe and accuracy is improving as the charges go higher.

 

[Triple BB]

I was shooting my 338 Edge with Berger 300 Elite Hunters today trying some different load combinations. It has about 120 rounds on it. I usually shoot two shots at a 100 and if they look good, I'm going further out. Had one 3 shot group do 1 3/16" at 400 yards. But then had a different load combo shoot 2 1/8" at 400 that shot 2 3/4" at 680 yds. I also had some combo's that shot all over the place. About the only thing I know; this gun is better than my abilities.

 

[Mikecr]

This being a hunting site, and the subject about accuracy, I have to point out that ACCURACY is not PRECISION (grouping).
So when you declare a .434 3 shot group, did you hit what you were aiming at with it? What was the accuracy with it?
Was the accuracy of the .434 group better or worse than the .618 group?
Were these hot bore groups or cold bore?

 

[MagnumManiac]

My Edge was a genuine 1/4 MoA shooter.
Best accuracy was with 300g Berger OTM, however, these were rubbish on game.
Sold that rifle last year.
My 338WM's (3) are 1/2-3/4 MoA without much trying.
My custom 338-416 Rigby Improved is less than 1/4 MoA with a custom CNC turned solid of 323g weight. It puts 10 shots into a ragged hole at 100. However, this rifle is getting tired now and shorter bullets no longer shoot as good. It's not done yet, but well on the way. Currently hunting with the 265g ABLR.
The 338 calibre is one of the most accurate medium bores.
I'm building a 338 Norma Improved next. Already got the action.

Cheers.

 

[MagnumManiac]

Duplicate

 

[WildBillG]

Mikecr when working up a load all that materrs is you hit the paper and have a point to aim at. You adjust your sights to hit where you want to hit once you have a load you want to use. Yes my Seirras hit where I was aiming. The 300 EH Bergers did not as I had no idea where they would hit compared to the 250 GKs. There is no point adjusting my sights yet as I still have to figure out velocity and a final load.

 

[sp6x6]

I have 2 -338NM.Shoots well,have shot 1 1/8 at 400 but not always.Taken about 20+ animals with the 300otm,cant recall a second shot.Elk at point blank with best blood trail ive seen to 850 yrd .I am trying the bulldozer,shot bull with 240 gr.last season but only 200 yrd.

 

[etisll40]

My Edge was a genuine 1/4 MoA shooter.
Best accuracy was with 300g Berger OTM, however, these were rubbish on game.
Sold that rifle last year.
My 338WM's (3) are 1/2-3/4 MoA without much trying.
My custom 338-416 Rigby Improved is less than 1/4 MoA with a custom CNC turned solid of 323g weight. It puts 10 shots into a ragged hole at 100. However, this rifle is getting tired now and shorter bullets no longer shoot as good. It's not done yet, but well on the way. Currently hunting with the 265g ABLR.
The 338 calibre is one of the most accurate medium bores.
I'm building a 338 Norma Improved next. Already got the action.

Cheers.

Hard to understand why you sold the 338 Edge?

 

[MagnumManiac]

Hard to understand why you sold the 338 Edge?

Didn't need it anymore, it was made redundant by my other build.
I'm not one to hang onto stuff I won't use.

Cheers.

 

[19 Badger]

If it is a custom rifle and the smith developed a good load for it I would hope for 3/8 to 1/2". I have seen it many times where someone pays good money for a rifle to be built but doesn't know how to load quality ammo (or buys factory ammo)for their custom build then complains that it only shoots a 1" group @ 100yrds. Is that the smiths fault? Nope...

 

[Cowboyblaster]

I just built a 338 RUM on a Weatherby Mk V action it has a Jury barrel 1 in 9.35 twist. Bob Jury is well known in Alberta for making great barrels. I don't have 50 rounds through this rifle yet and it has given me a .434 3 shot group with Sierra 250 GK. Today while looking for a load with 300 grn Elite Hunters it gave me .618 3 shot group with RL 33 at 96.0 grains. The Sierra group was using RL 25 at middle of the road Nosler data. I am using Bertram brass. I want to use Fed 215 M primers but they don't fit in all of my brass they are to big.
Any way should I be super happy with these groups or are the big 338s capable of even better. I still have a ways to go to get to max load I believe and accuracy is improving as the charges go higher.

I've been doing alot of talking to guys like yourself who i believe to be more knowledgeable or experienced than myself about load recipes for my 7RUM and those claiming to be max loading with h1000 or RL25 seem to also be claiming the highest velocities obviously but also the tightest groups

 

[Mikecr]

You adjust your sights to hit where you want to hit once you have a load you want to use.

If only it were that simple..
It is not
An accuracy system and load can be (and often is) entirely different from a precision sys/load.

 

[WildBillG]

Cowboyblaster I would have thought some of the slower powders would have given better velocity out of that cartrage. Those 2 powders do work well in a lot of cartrages though. If you can find any I would try Retumbo.N570.RL 33 or H50BMG with 160 plus grain bullets. Also that is a cartrage like the 257Wby where I would take my time shooting groups. N570 burns really hot and will heat up a barrel fast but is accurate as a rule.

 

[Cowboyblaster]

Cowboyblaster I would have thought some of the slower powders would have given better velocity out of that cartrage. Those 2 powders do work well in a lot of cartrages though. If you can find any I would try Retumbo.N570.RL 33 or H50BMG with 160 plus grain bullets. Also that is a cartrage like the 257Wby where I would take my time shooting groups. N570 burns really hot and will heat up a barrel fast but is accurate as a rule.

Thanks i completely agree with taking time when shooting groups especially because this is the triangular barrel XHR i beleive probably heats even quicker than the average light barrel .i was walking and talking 200 yards between each shot to avoid overheating a barrel i plan to sell as a built rifle with developed ammo (100 rounds ) scope,sling,bipod,dies,load data ,chronographed and doped out to 1200 yrds because i dont know anyone who could shoot it accurately beyond that even though the rifle and cartidge could