load data for 7mm LRM

[moombaskier]

I just measured my original hydro formed 375Ruger headstamp brass and their newer 7LRM headstamp brass. When I neck turned them I just took the "highside" off it. Both types of brass finished at .018" neck wall thickness. Outside before bullet seating is .313 and .315 after seating. Outside measurement on all after firing is .318
When Gunwerks smithed my barreled action they told me that I would need to turn the necks on the 375Ruger brass(just the high side) and when I ordered the newer 7LRM brass they said I would still need to turn, but their new reamer...should I build another...didn't require neck turning. I do not know the particulars...sorry.

 

[AZShooter]

Thanks Moombaskier,

You told me what I wanted to hear. Sounds like Gunwerks enlarged the chamber neck dimension.


Thanks for sharing.

Ross

 

[agentcooper]

Longtime member although first time poster. (I'm a bit of a wallflower) I just got back a 700 that I had Gunwerks rebarrel to a 7LRM. I am shooting the Barnes 168 LRX and Retumbo and have attached a picture of the 4 shot group at 100yds. I usually shoot 3 shot groups but I am getting used to a 2lb trigger and find that I have had a few misques on my part. The extra round is to eliminate the "I wish I could have that one back..." thought from my mind. I am using 71.5gr retumbo with a 215GM Federal primer at 3.300" OAL. Group measures .385" center to center and my velocity average is 3052fps with an sd of 16 and an es of 38. I am not too concerned on the chrony readings on the spread as the sun was peaking in and out causing some less than ideal conditions. Just wanted to share this info with anyone else looking to load this bullet in their 7mm LRM. I have H1000 on hand and was looking to try it also but with these results I am going to stick with what I got.

I sent my 700 to Gunwerks and had them install an 8.75" twist 26" Rock Creek barrell w/ a brake & 8 flutes, one of their LR1000 stocks bedded with pillars installed, Cerakoted, and I put a Jewell in it when I got it back. I have ran factory Senderos my whole life and this was my first custom build. I have to say I am very satisfied with the finished product. When going A la Carte as apposed to a complete system with them I found that their prices were reasonable when comparing to other gunsmiths but with the customer service and support I received it more than made up for any increase in cost.

 

[bamadawg2009]

Well it's time to dig up bones I finally got my LRM Sunday and got a chance to shoot it today. It took some settling in but after about 12 shots cleaning between every 3rd shot, my last 3 at 100 all went in a .5" hole. I'm shooting 70.5 gr H-1000 with 175gr nos LRABs with fed 215s and no signs of pressure. I will chrono it next time and see if I can push it a little hArder with the same accuracy and no pressure.

 

[speeders]

Well it's time to dig up bones I finally got my LRM Sunday and got a chance to shoot it today. It took some settling in but after about 12 shots cleaning between every 3rd shot, my last 3 at 100 all went in a .5" hole. I'm shooting 70.5 gr H-1000 with 175gr nos LRABs with fed 215s and no signs of pressure. I will chrono it next time and see if I can push it a little hArder with the same accuracy and no pressure.

bama,

What make of barrel are you running. Thats refreshing news. I hope to get mine to the range this weekend. I have some 168 Nosler LRAB's, 180 gr vld's and 180 gr hybrids to try out.

 

[bamadawg2009]

bama,

What make of barrel are you running. Thats refreshing news. I hope to get mine to the range this weekend. I have some 168 Nosler LRAB's, 180 gr vld's and 180 gr hybrids to try out.

It's a 26" Shilen #5 contour

 

[c-ne-elk]

I just ran into this post. Interesting the struggles others have had.

I have a 7 LRM made by Spoon's Custom Guns from a reamer purchased from Gunwerks and have been shooting it for about 16 months. A buddy of mine has one made from the same reamer that he has had for about 12 months.

We both shoot 72.0 g of H1000 with 180 g Bergers with no issues as long as we do not crowd the bullet too close to the lands. And yes you should be able to get 3100 fps out of this load, we do. I get 3110 fps, without pressure signs. Below is a photo of the turret I had made after correcting the velocity to my impact points at 500 to 900 yards. Trust me, I would not have spent $75 on a turret if it was not correct.

Accuracy is off the chart. 1 hole at 100 yards and the accuracy holds up out to at least a 1150 yards (we don't shoot any futher than that so we don't know)

The only difference is that we did notice some pressure signs with my rifle when I used Federal primers, with the CCI primers we have not had any issues. Seems strange but I went back and forth between Federals and CCI and the results were always the same.

We are not turning any brass, we are using dies from Gunwerks, dumping powder, seating a bullet and letting it fly!

BUT I will mention...we only get about 5 loads out of a piece of brass before the primer pockets get too loose to safely use.

 

[bamadawg2009]

I just ran into this post. Interesting the struggles others have had.

I have a 7 LRM made by Spoon's Custom Guns from a reamer purchased from Gunwerks and have been shooting it for about 16 months. A buddy of mine has one made from the same reamer that he has had for about 12 months.

We both shoot 72.0 g of H1000 with 180 g Bergers with no issues as long as we do not crowd the bullet too close to the lands. And yes you should be able to get 3100 fps out of this load, we do. I get 3110 fps, without pressure signs. Below is a photo of the turret I had made after correcting the velocity to my impact points at 500 to 900 yards. Trust me, I would not have spent $75 on a turret if it was not correct.

Accuracy is off the chart. 1 hole at 100 yards and the accuracy holds up out to at least a 1150 yards (we don't shoot any futher than that so we don't know)

The only difference is that we did notice some pressure signs with my rifle when I used Federal primers, with the CCI primers we have not had any issues. Seems strange but I went back and forth between Federals and CCI and the results were always the same.

We are not turning any brass, we are using dies from Gunwerks, dumping powder, seating a bullet and letting it fly!

BUT I will mention...we only get about 5 loads out of a piece of brass before the primer pockets get too loose to safely use.

My accuracy goes all to hell with anything over 70 grains of h1000 with the 175s, as in .5 to almost 3"s. My next load to try is 180gr MKs with h1000 it shoots same point of impact with 70gr of h1000 and 180s as the 175 and just as good accuracy, but haven't tried anything hotter than 70grs.

 

[trappers son]

I just had Dan Pederson build me a 28 inch heavy barrel on a weatherby action. I had Dave Kiff build me a reamer that blows the shoulder forward on a 7mm weatherby case and it has pretty similar case capacity as the 7lrm but the brass is more consistent and expensive... I blew out the cases using a light load of reloader 33 to form to the chamber. He coined it a 7mm weatherby rogue... sorry RBROS not my call.... The cases are not fully formed to chamber diameter but they hold 91 grains of case capacity. I have a lot of work to do in load work up but I was reading some of the brass issues and decided to try my luck on this chambering.... I will report on my load work up if anyone is interested.... I will be using similar charge weights of h1000... After I find a rough node I will look for the best seating depth and post pics....

 

[cgpaul]

Interesting read...I`m working with a 7 Wby,9 x26 PAC-NOR. My load for the berger 180 Hy-Brid is 70.2 grn of H1000. Just shot my first 400 yrd groups yesterday, 2.25 inches, but have not cronied yet. I would be happy with 3K.
I hope you fella`s get the results your after, considering the pain involved.

 

[AaronSkipDavidson]

Guys,

Breaking news. We've tracked down the problem some are having with 7LRM. The pressure problems are stemming from a neck dimension from a loaded round that is too big for the chamber. The neck in a Gunwerks 7LRM chamber will be .322 at the shoulder junction and .321 at the mouth. Some brass from the current lot is measuring .319-.322. Way to big! The spec is .316", also, the last bunch of Bergers have been measuring at .2845! Our freebore is .2845", again, too tight. The solution is to neck turn your brass to obtain a loaded neck diameter no greater that .316" and shoot some of the new 180 Hybrids that are measuring 0.284.

We've traced the root cause back to one of two punch dies that are drawing the necks to dimension. That means that half of our brass production was batched out of spec. We will have new brass to spec in the October ball park. Please call me directly if you have any questions. 307.762.1406

 

[trappers son]

Glad you fellas got the issues worked out. You guys build nice guns and I love the video with the young man shooting that bull at 1300 yards.... That was great stuff... Running a business is hard when production of essential components is out of your hands, and berger hybrids get hard to find.... Hope you have found enough to keep you going and everything is running smooth again.....
Hey CG, my last barrel was a 28" custom chambered in 7mm weatherby.... It shot real good groups at a thousand during comps.... My smallest group from a bipod was 4.5 inches four shot group, I flubbed the last one but they all were in the x except the last shot (5th still in the 10), and I was using 70.1 grains of h1000 .120 off the lands... that was as close as I could get her.
I was pushing 2950 or a bit less with great sd's... My high node was 72.5 for hunting and it was pushing 3050 with same groups and sd's but it was too hot on a barrel for quick shots... I took her out to a mile for a few times on a 12 inch target..... It was fun and quit the learning experience.... Not bad for a hunting rifle that my father used for many years before I inherited it...
I went out after forming brass and loaded up to 69.5 grains in .5 increments. I have a shorter throat designed for the hybrids that is .2 inches long so I went off the lands .015 thou and shot groups over the chrony at 200 yards.... I found my low end node at 68.5 grains and it shot .75" from outside to outside so it is a quarter to a third inch gun. Hope it stays that way at distance... The top velocity from the chrony was 2912 and the lowest was 2907 so it looks like a good comp node.... I'll get back to you when I find my high end node for hunting....
The trick I found to run the bergers in a long throated weatherby was to only neck size and leave a decent portion of the neck near the shoulder un-sized so the round would sit truer and align with the bore and then use a bullet concentricity gauge to make sure there was no bullet run out.... my cases were always checked and sorted by weight.... the nice thing is the brass is very consistent in weight and the primer pockets were always drilled and centered... left no prep work at all until the necks needed trimmed. I would still get great group even if I used virgin brass without neck trimming.

 

[agentcooper]

Thanks for the post Aaron! I called you guys about a month back and spoke with Jeremy. He instructed me to do exactly as you stated with turning the necks. I was having some major ES issues. The gun was shooting 1/4 MOA when I got lucky with the individual cases that were loaded, but the next group could have been up to 24" of vertical at 1000yds and around 150fps spread on my chrony!
I called up 21st Century Shooting and ordered one of their neck turning kits, very well built components with precise adjustments that are easy to dial in. Tremendous value, in my opinion, if someone is looking at buying neck turning components. After turning all necks to .3155" my issue is solved!
I've been shooting the Barnes 145gr LRX with 74.5 grains Retumbo, 215gm primer, and loaded to 3.300" OAL. My shot corrected velocity is averaging 3298fps and the rifle is consistently 1/2 MOA or better with my lousy finger pulling the trigger! The chrony is reading ES around 20fps and if I had to guess, I would say that is close to reality.
Thanks to you folks at Gunwerks for the outstanding rifle! Anytime I called and had a question (I had a million, ask Melanie. Haha.) it was answered prompt and accurate.
Heading to Wyo. in two weeks for a region H muley hunt to put the new rifle and G7 rangefinder to the test. Hopefully, if there is time after the hunt (My dad and I are going DIY on foot and are taking up to two weeks if necessary to find what we're looking for.) we'll stop by the shop in Burlington and say hello........unless you fellas are out chasing dreams yourself.
Good luck to everyone on LRH with their upcoming hunts!

 

[cgpaul]

Trapper....not to steal this thread....but thanks for the info. Again, my first go-round with the Hy-Brids, so was happy with initial results. I`ve been shooting Sierra 175`s at 3020 for hunting load. Extreamly accurate bullet in my rifle. I have loaded my stuff to get the most use out of the brass...primer pockets go first, so not pushing to hard.
I`ve some 180`s loaded to try over the cronie tomorrow...should the rain stop.
BTB. very good shooting at 1K.