I just finished building a 7 LRM and was wondering if anyone has any experience with this caliber. I want to shoot the 180 Bergers and I'm starting with H1000, does anyone have any load development info? I have heard that Gunwerks is shooting 72 grains of H1000 with the 180 Bergers. Any other info, max load etc?
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7 lrm
- Thread starter WTB
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Recently Gunwerks modified their reamer with a larger neck diameter. The reason is that some of the Hornady brass has shown up with thicker walls. There were some reports last year of high pressure with sticky bolts and flattened primers when some handloaders tried the original Gunwerks suggested load with H1000.
I would suggest you find out what your chamber's neck dimension is then determine if there is sufficient bullet release clearance before you begin loading.
A friend had SOME of the brass that was IIRC running .017" thick and his chamber had the tighter neck dimension! We had to turn all his brass for proper bullet release clearance.
A simple test if you have fired some rounds is to see if a bullet will slip into the fired case mouth without resistance. If it is tight you risk an over pressure situation with that random piece of brass that is just a bit thicker than the rest. If nothing else it will cause irregular velocities and flyers.
I would suggest you find out what your chamber's neck dimension is then determine if there is sufficient bullet release clearance before you begin loading.
A friend had SOME of the brass that was IIRC running .017" thick and his chamber had the tighter neck dimension! We had to turn all his brass for proper bullet release clearance.
A simple test if you have fired some rounds is to see if a bullet will slip into the fired case mouth without resistance. If it is tight you risk an over pressure situation with that random piece of brass that is just a bit thicker than the rest. If nothing else it will cause irregular velocities and flyers.
They switched this year you'd have to ask Gunwerks or PT&G. If you are turning them and a bullet will slide into the neck of a fired round you will be fine. If you got to 73 gr and there is no pressure I am pretty sure you are fine.
firstcoueswas80
Well-Known Member
Don't over look retumbo and us 869, if h1000 leaves you wanting more....
Update: My 7LRM is shooting unbelievable, however I'm not getting the velocity that gunwerks says they are getting. The gun seems to like 71.5, 72.5 and 73.0 grains of H1000 but on the low end I got 2887 and on 73.0 grains 2980 over my Oehler. ES on the 3 loads were all less than 9fps. 71.5 and 73.0 7fps and 6fps. The barrel is 26" long and has 46 rounds on it so far.
Two ways to go. Relax and use it with the wonderful H1000 which is an extreme powder. OR get closer to wearing out your barrel trying RL-33, Retumbo and US 869 till you get the velocity you think you need. Crunch the ballistics numbers and set your mind at ease with its downrange performance.
holdinsteady
Active Member
My 7LRM will be ready by the end of the week.....got everything I need to start load development except H-1000.....just can't find it anywhere. I do have Retumbo, US869, H4831sc and RL33. Any thoughts on starting loads with these powders and 168/180 Bergers?
Thanx, Jerry
I have no experience with the other powders in the LRM. I just switched to a new lot number of H1000 and my velocities are up to 3125 with 72.0 grains. I tried several loads in my LRM and 71.5-72, and 73 shot the best. Is Gunwerks building you LRM?
holdinsteady
Active Member
My local smith is building the rifle for me. Bought reamer, dies and brass from Gunwerks this summer.....looking forward to getting the rifle up and running for this fall elk and mule deer hunt. Where are you finding H-1000? I haven't been able to locate it anywhere since I started this project.
Jerry
Jerry
firstcoueswas80
Well-Known Member
Up to 72 grains of Retumbo and 82 with us 869 were both safe in my rifle with 175 LRAB. I'm actually heading out in the morning to do some testing.
I haven't had any trouble finding H1000, a couple local vendors here have had it every time I've checked. The bullets have been the component that has been hard to find for me. Gunwerks is shooting the Berger 180 hybrid exclusively in their LRMs. The LRM was designed around this bullet. I shot the 180 VLDs and the 180 Hybrids and there was no comparison. The hybrid out shot the VLDs everytime I shot them.
holdinsteady
Active Member
Thanx for the info.....and last I heard was Berger was supposed to be doing another run on the 180s during Aug......hopefully they will be on the shelves soon.
