Len - 7mm

[Len Backus]

Bob's 176 grain 7mm bullet uses Sierra's thicker 30 cal jacket.

On a related matter, I "dusted", as you say, some 162 A-max's a while back with velocities as low as 3200. Last week I received a replacement box of bullets from Hornady. I talked to their bullet guy and found that they had been having a few problems with some apparently sharp-edged barrels and they made some type of change. We'll see.

[ 05-07-2004: Message edited by: Len Backus ]

 

[speedbump]

I like Len's project theory too. I think many of us think in similar terms here.

I've run C176s over 3,400 in a 30" barreled 7mmRUM with ALL the bullets holding together. It shoots better in the low-mid 3,300s though.

Roughly 17.5 MOA elevation at 1,000 & 1/3 less wind drift than a 6.5-284. That's head-to-head comparison in a sanctioned match, not numbers crunched on paper.

 

[old fart]

your 7/338 lapua - this is a improved case your building ,did you move the shoulder forward and at what angle -thanks

 

[Len Backus]

My shoulder is forward and at a 35 degree angle.

 

[reed mosser]

I think my gunsmith was dusting bergers. I didn't know the 176 grain used sierra jackets. if they do I don't see any problem hitting 3500fps with a 9 twist. I have 30-338 laupa imp with 30 inch barrel that shoots great with 150's from 3750 to 3850 fps. I don't think you will have a problem with accuracy that laupa brass is great. As far as sevens being accurate everyone I ever had 7 wsm and 7 rem mag would shoot at least .25 inch no problem. I think you have great long range hunting cartidge out to 2000 yards. My gunsmiths version is shortened with a 35 degree shoulder, his 7mm shortened laupa holds about 90 grains of powder. I think he gets around 4000 fps with 120gr nosler and with 175 sierra gamekings he is getting around 3400 FPS. I hope this helps. Good Luck hope is shoots great.

 

[CanadianLefty]

Len, any updates for us?

 

[Len Backus]

I dropped my project because I was getting high pressures for some reason. At about the same time I was trying to work through the pressure problem, I realized I wanted to continue having low enough recoil to see my bullet's impact on game. I hunt alone at home and don't have a spotter partner. A mortally wounded deer in my 2 to 3 foot marsh grass is easier to find if you know which direction he went and you have the confidence of having seen the good hit. I am colorblind!

So at the time of my pressure frustration I decided I wanted to go lighter with my rifle (then 18 pounds) and I could never do that with the faster and higher recoil 7/338.

I ran the recoil numbers and found the following. The recoil would be the same for these 2 very different rigs.

15 pound rifle (my new, lower weight), 76 grains powder, 176 grain bullet, 3,100 fps.

21.5 pound rifle, 98 grains powder, 176 grain bullet, 3,450 fps.