load data for 7mm LRM

[bamadawg2009]

So my new play toy should be ready in a couple of weeks. Im having a gunwerks 7mm Lrm built but do to the current powder situation I cant find any Retumbo for my baby. My question is does anybody have any load data for the 7LRM using the new 178gr Nosler LR Accubonds using H-1000? My gunsmith is using 72 grains of Retumbo getting 3050fps, he told me to start with 70grains of H1000 and start from there. Does this sound close to about rite? He switched from H1000 because he was getting pressure without velocity with 180gr bergers and never loaded the Noslers over h1000.

I just dont want to blow up a $3500 gun with the first shot. I have contacted Mike at gunwerks about this and he said they havent done any load data yet with them.

 

[AKGuide]

I'd try get my hands on some US-869 and start at 72 grains and work up. It isn't an extreme powder, but with a slightly slower burn rate than retumbo you might have some luck with it. I don't think that you will get compressed loads as this powder is very dense and a ball powder. N570 at 72 and work up might work well as it is a touch slower than retumbo also.

Reuben

 

[bamadawg2009]

Thanks Reuben Ill see what I can get ahold of and go from there, but with the way powder is going these days I might come up to Alaska and see if I can find gold easier.

 

[AKGuide]

I here you there. The powder supply up here is gone as soon as a shipping box is opened. I am having a very difficult time getting H4831 or R22 for my upcoming project. H414 will have to suffice for now. Good luck on the powder hunt.

Reuben

 

[tdean]

This is my first post on here.



funny you said you didn't want to blow up gun on first shot because that's about what I did. New gunwerks barreled 7 lrm. New gunwerks brass 72 h-1000 3.420 .017 off lands cci 250 Berger 180 . First shot blew primer out, hard bolt lift , huge smiley face, and I thought well that sucks first shot on 27" Krieger



I believe it was partially my fault. Bullets were extremely hard to seat. the hornady dies were cutting into case necks causing material to get pushed in between bullet and neck
And the first bullet I tried was one of the worst looking ones



Was unbelievably hard to unload them with hammer. I have since run all through suplied expander button, brushed inside of necks, trimmed necks just taking high side off, scraped burr and rough edge off seater die and swapped out bullet seating piece with the other one that came with set, and just generally slowed down and taken my time. All bullets seat great now. I ordered a .317 bushing so I can have even less tension and use the non expander button. Neck tension measured .001 but the neck is so long it has a lot of gripping surface to hold bullet in my limited opinion


70 h-1000 was pushing 180 @ 2975 no psi sign
71 h-1000 3040 fps no psi sign
72 h-1000 3060 fps barely shows ejector mark on brass

I never seem to be surprised what issues I can have or myself

Will say gun broke in awesomely, they cut good chambers as far as that goes

And all groups have been .5 moa even when cleaning every shot


I wil do a more comprehensive report and will try retumbo maybe that will give me more speed with less psi

 

[tdean]

Hodgdon Powder


Has 8 lb kegs in stock

 

[tdean]

see pic of what i was trying to say

 

[bamadawg2009]

Thank man I noticed the same thing you said about the seater die grabbing the outside of the case neck when I was loading the 180 sierra matchkings, but I did not notice it when I was loading the noslers. I have never had this problem before in 17years of reloading but I will give them a try and see what happens.

You are also seating the bullets a little deeper than I was told to by my gunsmith. Im seating mine at .010 off the lands and Im wandering if this is why he said hes having pressure signs because the bullets are too close to the lands. He says 70.5 with H1000 is as high as he can go without any pressure signs on the case but gunwerks load is 72.4 if Im not mistaken.

Hopefully Ill have it in my hands in a couple weeks and can do some tinkering of my own and see what happens.

KEEP ME POSTED ON YOUR PROGRESS

 

[tdean]

Aron at gunwerks said the max oal touching the lands was about 3.45 per the reamer design with Berger 180 but it varied quite a bit depending on the lot of bullets. Mine hit the lands at 3.437 I believe. So I followed the advise on their many videos which said start with .020 off the lands. I loaded some at .020 off .040 off and .060 off to try this weekend

And I got some retumbo and some nosler 175 lrab just to make my life more difficult. Will post this weekend on results hopefully.

 

[tdean]

I went out and shot groups at 200 yds this weekend and it was pretty much a disaster. Best group was .8 moa if you rule out a flyer I had a 4 shot group at .5 moa it seemed the good groups had Es of 40 fps + though. It seems that the third and fourth shots were flyers. But most other groups were around 2 moa. Velocites were slower than gunwerks advertises no way I could get to 3100 with 180 Berger 72 gr h-1000 sticky bolt and ejector mark and 73 retumbo same thing, of course seating depth has a large effect. Best speed was 3050 average. Still not complaining. Based on stringing I think I may have a bedding issue. I ordered a dial indicator to check. I bedded it my self so It's a really good possibility.

 

[tdean]

I went back and re bedded it and in the process found some places where the action was touching stock other than behind lug and tang I dremeled that out and shot a .5 moa group at 100 3 shots then 4 th made it 1 moa. I am now in process of bedding 2 piece bases and lapping rings to make sure I'm not putting any stress on action with scope. I figure if you are really into this game it takes about 3 years to get semi good at tuning rifles. Or in my case I'm still hoping to get semi good. Learning is expensive

 

[tdean]

pic of setup

 

[bamadawg2009]

Yeah I hear ya I don't have that much patience but I try little things here and there. I've got everything loaded and ready to go just waiting on my smith to tell me to come pick-up the rifle.

 

[moombaskier]

Sorry to hear you're having issues. Gunwerks has modified their 7LRM reamer since they smithed my barrel and action. I need to turn my necks, just taking the high side off. That gives me .002" neck tension. Gunwerks also had their seating depth set for a .025" jump to the lands. My seating depth was best at .020 jump with the 180VLD. My set up shoots amazing.