.338LM + 300 Bergers = fail

[ECG]

I normally shoot 285 Hornady match but I decide to give these 300s a try. Here's the issues I had:

1. Could not get a consistent seating depth measurement. Usually I get a slight deviation of a few thousands when measuring a new bullet.

2. When I finally decided on a OAL it was past mag length.

3. Best group I could get was a MOA @ 100Y.

Barrel twist 1:10, 26"
Seated at 3.000 off the Ogive
Powder H1000,
Started at 92.4 grains and worked down by 0.8gr

Came close to a node at 86.9gr (best group one MOA)

I stayed away from Berger bc they are not well stocked in .338 here so I'm new to them. Any thoughts from people that shoot the .338LM?

 

[Defuzer]

OAL 3.000?

doesn't look right? just asking

 

[ECG]

Off the Ogive not Meplate.

 

[psinclair]

1-10".....button or cut rifled?

My Bartlein 1-9.7" bugholes those 300 OTM's.

 

[1SMALLJOHNSON]

You'd probably better get a comparator from Sinclair. Don't measure to the tip. Measure as you would with a "ring gauge", somewhere off the ogive. I take it you're also attempting to "jamb" the bullets into the rifling? If not, how far off the lands are you seating? I think some folks will debate a 1/10 twist for a 300 grainer, and it's true that a 10 twist is not optimized for a 300 grainer. But, there are a myriad of questions to pose to you: What's the round count on the tube? What's the COAL? What's the chamber? Did you happen to measure the throat with some "known" bullet when the chamber was fresh, and able to measure the throat again, with X rounds shot through it? There's nothing wrong with Bergers, but you've got to work within their design intent.

 

[Ryguy]

Do you mean, 3.000 at the ogive? I have noticed a deviation of .007 amongst Berger bullets as well. Some batches are better than others but recently, it has been worse than normal. I have to separate each one based on bearing surface and weight. Weight is usually very close with only a .1 or .2 grain difference. With H1000, some people get good results while others do not. I was in the do not category. Retumbo, RL 33, and VV N570 are universally accepted as 338 Lapua powders but H1000 is either great or terrible. When I last ran out of 300gr OTMs, I switched to the 300 SMK and have had good luck.

 

[ECG]

As I stated I measure off the Ogive not the Meplate. They are touching with minimal interference. We can rule out any "Newbie" errors. Round count 184.

 

[ECG]

Ryguy, thanks. That's what I've heard. I'm getting .015 deviations off the ogive. I think I'm in the no fly zone for Berger 300s. Just out of curiosity, what's your charge weight in the 300 SMK's? Should have stuck with my 285s.

 

[mwilkins]

30" Bartlein 1:9.5 twist
Berger 300 OTM seated to 2.915 at the Ogive. Gives me a little jump to the lands
OAL of 3.750 - Mag is 3.773
93 gr of Retumbo
Lapua Brass
Fed 215 Mag primers


My little friend loves them Berger's.

 

[Layton]

Mine loves Bergers but I they do vary quit a bit. Also, I tried H1000 and am in the no luck category. Retumbo and N570 work like a charm.

L

 

[Ryguy]

My first barrel was 91.5 gr, H1000 with mediocre accuracy (.75, 2750fps) then 92gr VV N570. This second barrel would not take H1000 at all so I switched to 96 gr RL33 with .3 accuracy showing in the 2800's maybe low 2900's, hard to remember exactly. With a 1:10, the 285's may very well be perfect. Some people cannot get good accuracy from Bergers and it seems you and I are in that category. I have had good luck with 30 cal Bergers but the .338 showed me no love. It has been a while since the 338 has been out but I think Bergers had to be single fed but the SMK could be mag fed for sure.

 

[ECG]

Gents, thank you very much. I don't post on here that often but you guys are giving some quality feed back. I greatly appreciate it! I may run out and grab a pound of Retumbo just to see what happens before throwing in the towel on these.

 

[Layton]

You'll most likely find a sweet spot somewhere between 92g and 93g. That's seems to be the most common.

 

[zackm]

My guess and it is a guess that the problem is a combo of the 1:10 barrel and the h1000. H1000 is a "fast" powder by 338 lapua standards and the 300 gr bullet is a "heavy" bullets and in my testin i have found that in general slow powders like heavy bullets and fast powder do better with lighter bullets. Justlike heavier bulletsblike faster twist rates. This being said i would start by going to a slower powder i.e. retumbo / wc867.

I have a lot of good results retumbo at 89.3 gr of retumbo and the berger 300 gr otm seated at 3.700 coal / 2.848. If this load seems to work in a lot of rifles. If it does not for you there is nothing wrong with the 285's. by the way my barrel is a 1:9 27"'s long i get 2730 wit the the retumbo load.