7LRM (Long Range Magnum) - Pic & Info thread
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br45zy
Member
I had been shooting a Gunwerks LR100 in 7LRM that my friend has and really liked the cartridge's performance so I had one built in January.
Since I put this rifle together for a hunting rifle I left the free bore alone. I decided to keep this rifle as simple as possible and this way i can always use Gunwerks or my friends ammo. I am able to seat the bullets for my rifle around 0.040" longer than my friend can for his LR100. The difference is so small that there really is not any performance to be gained from the seating depth and our rifles shoot almost identically.
If you really wanted to maximize the potential of the case you could get your gunsmiths recommendation on the maximum free bore and how much additional speed you could expect to see.
Using Gunwerks load data my rifle is getting 3083 f.p.s. with the 180 grain Hybrid at just under 0.5 MOA accuracy with a 26.5" Brux barrel. I was able to to get the Hybrid above 3140 f.p.s. but the groups began to open up so I backed the charge back down.
Overall I really like the speed I am seeing vs. the powder charge it takes to get it there. I have had people tell me they are getting almost the same velocity from a 7 Remington Magnum but in my experience I have only been able to get the 180 gr. VLD and Hybrid to around 2880 f.p.s. at best from a 26" barrel while maintaining acceptable accuracy and not tearing up the brass.
Since I put this rifle together for a hunting rifle I left the free bore alone. I decided to keep this rifle as simple as possible and this way i can always use Gunwerks or my friends ammo. I am able to seat the bullets for my rifle around 0.040" longer than my friend can for his LR100. The difference is so small that there really is not any performance to be gained from the seating depth and our rifles shoot almost identically.
If you really wanted to maximize the potential of the case you could get your gunsmiths recommendation on the maximum free bore and how much additional speed you could expect to see.
Using Gunwerks load data my rifle is getting 3083 f.p.s. with the 180 grain Hybrid at just under 0.5 MOA accuracy with a 26.5" Brux barrel. I was able to to get the Hybrid above 3140 f.p.s. but the groups began to open up so I backed the charge back down.
Overall I really like the speed I am seeing vs. the powder charge it takes to get it there. I have had people tell me they are getting almost the same velocity from a 7 Remington Magnum but in my experience I have only been able to get the 180 gr. VLD and Hybrid to around 2880 f.p.s. at best from a 26" barrel while maintaining acceptable accuracy and not tearing up the brass.
bigngreen
Well-Known Member
With two 7 LRMs spec'ed with a turned neck and a 180 seated out with no bearing surface below the neck shoulder junction and 25.5 inch barrels we were able to push over 3000 fps but nearing 3100 fps pressure signs became to much and brass life was taking a hit. The accuracy in both was in the 2980 fps range. I pushed mine with Retumbo and R33 in the 3150 range but it's to much. The 7 LRM is at the same performance level as a well built 7 Rem mag but the LRM has an excellent design and does not have a belt so I like it but it won't operate at the level I want.
Elkhunter1983
Well-Known Member
I was down to two or three cartridges to do a build with. The 7mm dakota or 28 nosler but I shoot a lot so potential barrel life is a downside. So is the cost and a availibility of brass. The only other im still toying around with is a 300 norma but again, barrel life and $2.00 plus for brass when you can find it.
Rockfish Dave
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- Dec 21, 2008
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Bump for any new updates or contributions.
firstcoueswas80
Well-Known Member
I had a 7 LRM built. Great gun, but haven't found the accuracy like I like yet. It is there, I just haven't squeezed it out yet. I've got the powder charge, just haven't found the COAL to give crazy small groups. Consistently sub moa though.
I've been using 70-71 grains of Retumbo with the 180 hybrid for 3060 fps.
I've been toying with up to 69 gr H1000 with the 180 Scenar as well.
I've been using 70-71 grains of Retumbo with the 180 hybrid for 3060 fps.
I've been toying with up to 69 gr H1000 with the 180 Scenar as well.
agentcooper
Member
I have a 700 built by Gunwerks in a 7LRM. I've been shooting the Barnes LRX 145 (3300fps) & 168's (3040fps) out of it. 0.020" off the lands and Retumbo in both, 75gr for the 145 and 70 for the 168. Both loads capable of 1/4 to 1/2 M.O.A. depending on how I'm shooting that day.
The brass for this cartridge has definitely driven me a bit crazy at times. FWIW I weight sort my brass to get consistent accuracy and velocity spreads. My 200 rounds fell into three definitive groupings: 246-249 grains, 251-252 grains, and 255-257 grains. Without sorting, both loads would shoot 1-1.25 M.O.A. with an ES of 125 - 150 fps at its worst. Also, as an experiment, I have determined if you use develop a max load with the lighter group of brass (Slight extractor mark) and charge some of the heavier brass with it, you will blow out primer pockets. Measuring case head dimensions and OAL of the brass were consistent across the board so there is definitely going on internally.
Aaron, Mike, Jeremy, and last but not least, Melanie were all excellent to deal with and the rifle itself is truly a fine piece of equipment. The cartridge's ballistic performance is definitely what I was wanting/expecting. (The LR1000 stock is far and away my favorite sporter type rifle stock as well) I would recommend them to anyone for a rifle build, even if you are going a' la carte on a build like I did and not wanting a turn key system. Just crossing my fingers that the next batch of brass I get is more consistent or better yet, more manufacturers start making 7LRM brass. Variety is the spice of life.
The brass for this cartridge has definitely driven me a bit crazy at times. FWIW I weight sort my brass to get consistent accuracy and velocity spreads. My 200 rounds fell into three definitive groupings: 246-249 grains, 251-252 grains, and 255-257 grains. Without sorting, both loads would shoot 1-1.25 M.O.A. with an ES of 125 - 150 fps at its worst. Also, as an experiment, I have determined if you use develop a max load with the lighter group of brass (Slight extractor mark) and charge some of the heavier brass with it, you will blow out primer pockets. Measuring case head dimensions and OAL of the brass were consistent across the board so there is definitely going on internally.
Aaron, Mike, Jeremy, and last but not least, Melanie were all excellent to deal with and the rifle itself is truly a fine piece of equipment. The cartridge's ballistic performance is definitely what I was wanting/expecting. (The LR1000 stock is far and away my favorite sporter type rifle stock as well) I would recommend them to anyone for a rifle build, even if you are going a' la carte on a build like I did and not wanting a turn key system. Just crossing my fingers that the next batch of brass I get is more consistent or better yet, more manufacturers start making 7LRM brass. Variety is the spice of life.
Rockfish Dave
Well-Known Member
- Joined
- Dec 21, 2008
- Messages
- 359
I have a 700 built by Gunwerks in a 7LRM. I've been shooting the Barnes LRX 145 (3300fps) & 168's (3040fps) out of it. 0.020" off the lands and Retumbo in both, 75gr for the 145 and 70 for the 168. Both loads capable of 1/4 to 1/2 M.O.A. depending on how I'm shooting that day.
The brass for this cartridge has definitely driven me a bit crazy at times. FWIW I weight sort my brass to get consistent accuracy and velocity spreads. My 200 rounds fell into three definitive groupings: 246-249 grains, 251-252 grains, and 255-257 grains. Without sorting, both loads would shoot 1-1.25 M.O.A. with an ES of 125 - 150 fps at its worst. Also, as an experiment, I have determined if you use develop a max load with the lighter group of brass (Slight extractor mark) and charge some of the heavier brass with it, you will blow out primer pockets. Measuring case head dimensions and OAL of the brass were consistent across the board so there is definitely going on internally.
Aaron, Mike, Jeremy, and last but not least, Melanie were all excellent to deal with and the rifle itself is truly a fine piece of equipment. The cartridge's ballistic performance is definitely what I was wanting/expecting. (The LR1000 stock is far and away my favorite sporter type rifle stock as well) I would recommend them to anyone for a rifle build, even if you are going a' la carte on a build like I did and not wanting a turn key system. Just crossing my fingers that the next batch of brass I get is more consistent or better yet, more manufacturers start making 7LRM brass. Variety is the spice of life.
Good post. I never have sorted by weight, but given your post I guess I have something to do after the kids go to sleep...
Would you recommend loading to the mean weight brass, or separate loads for each weight group?
agentcooper
Member
I had not before either. It's a subject of debate, I know, but I figured time to try something. I went with the mean grouping (251-252) simply because I had more pieces in that pile. ES stays under 30fps now. I'd imagine you could tune your powder charge a few tenths up or down to duplicate the ballistics in the other weights of brass but I haven't tried it yet. I have some of the older brass as well, when there was an issue with the thick necks. I found that weight sorting that brass after neck turning yielded the same results although, the weight groupings were completely different for obvious reasons.
Although I've never done it before, I believe that measuring case volume with a liquid media is the best way to sort for case volume. I just don't really have the time to do it and sorting by weight worked to achieve the results I personally was looking for.
Although I've never done it before, I believe that measuring case volume with a liquid media is the best way to sort for case volume. I just don't really have the time to do it and sorting by weight worked to achieve the results I personally was looking for.
BRNG525
Member
gun)Wow great post. I too have a 7mm LRM from Gunwerks and have been having some fits with my factory loaded ammunition. I was told it was a brass issue and that they were getting it worked out with Hornady.
I have been lucky so far with my reloads as they have all shot dead on. My max velocity spread has been 37 fps on the reloads so far. I will keep my fingers crossed.
I will have to check my brass this week to see if mine fall out to be the same as yours. Thanks for your time and sharing the information.
I have been lucky so far with my reloads as they have all shot dead on. My max velocity spread has been 37 fps on the reloads so far. I will keep my fingers crossed.
I will have to check my brass this week to see if mine fall out to be the same as yours. Thanks for your time and sharing the information.
agentcooper
Member
BRNG525,
What was the velocity spread on the factory loaded ammo? What are you using in your reloads? I know they load the Barnes 168gr LRX in factory ammo as well, and was tempted to buy a box or two thinking that perhaps I developed an unknown bad reloading habit. Sounds like it may have only confirmed what I already determined.
Let me know what you find with out with your brass. I'm really curious to hear if other people have turned to culling their brass by weight or volume with this cartridge and yielded favorable results as well. It just sucks to buy 400 rounds of brass and have it culled into six very different groupings, (200 from when they had the thick neck issue and 200 rounds after it was resolved.) and have less than 100 rounds in a sub-group to work with, I like to load in larger quantities than that to get more time at the range and less at the reloading bench.
I have faith Gunwerks will get it resolved. They are a small and very rapidly growing company and that is not lost on me as a customer. They do their best to get back in touch when they can but, I can only imagine dealing with issues like this brass keeps them from working with customers as much, and working with Hornady to ensure that the issues get resolved to ensure that said customers get a quality product in the end. After all, can't really blame them, they don't make the brass! I just hope the news of a resolution comes sooner rather than later. Also, can't wait for details on the new LRmax bullet whenever it arrives.
I'd also like to hear if anyone has formed any out of 375 Ruger brass and what that entails. I know Nosler is making brass for that now and even though it'd be a lot of expense and work, I would do it to get this rifle behaving consistently as it hits all of the performance benchmarks I am looking for.
What was the velocity spread on the factory loaded ammo? What are you using in your reloads? I know they load the Barnes 168gr LRX in factory ammo as well, and was tempted to buy a box or two thinking that perhaps I developed an unknown bad reloading habit. Sounds like it may have only confirmed what I already determined.
Let me know what you find with out with your brass. I'm really curious to hear if other people have turned to culling their brass by weight or volume with this cartridge and yielded favorable results as well. It just sucks to buy 400 rounds of brass and have it culled into six very different groupings, (200 from when they had the thick neck issue and 200 rounds after it was resolved.) and have less than 100 rounds in a sub-group to work with, I like to load in larger quantities than that to get more time at the range and less at the reloading bench.
I have faith Gunwerks will get it resolved. They are a small and very rapidly growing company and that is not lost on me as a customer. They do their best to get back in touch when they can but, I can only imagine dealing with issues like this brass keeps them from working with customers as much, and working with Hornady to ensure that the issues get resolved to ensure that said customers get a quality product in the end. After all, can't really blame them, they don't make the brass! I just hope the news of a resolution comes sooner rather than later. Also, can't wait for details on the new LRmax bullet whenever it arrives.
I'd also like to hear if anyone has formed any out of 375 Ruger brass and what that entails. I know Nosler is making brass for that now and even though it'd be a lot of expense and work, I would do it to get this rifle behaving consistently as it hits all of the performance benchmarks I am looking for.
BRNG525
Member
The velocity spread on the factory was 17fps. Average Speed 3009fps
The velocity spread of one ten shot string of my own loaded ammo was 37fps. Average Speed 3003fps
The velocity spread of a different batch of my own loaded ammo was 48fps. Average Speed 3064fps
Two different lots of brass loaded on two different dates but shot on the same day!
My loads consist of the Hornady Brass, Federal Match Grade Magnum Primers,
72 Grains of H-1000 powder and Berger 180 Grain Hybrid Bullets
I load on an Redding Press with Hornady Custom Dies. RCBS Digital Powder Scale, RCBS Hand Primer
I use an Oehler Model 35P chronogroph
I haven't tried any different loads as my rifle shoots these so well.
Did you ever try the 168 grain bullets, just curious as to how they shot?
I am going to weigh all of my brass this weekend so I will get back to you next week with what I find.
The velocity spread of one ten shot string of my own loaded ammo was 37fps. Average Speed 3003fps
The velocity spread of a different batch of my own loaded ammo was 48fps. Average Speed 3064fps
Two different lots of brass loaded on two different dates but shot on the same day!
My loads consist of the Hornady Brass, Federal Match Grade Magnum Primers,
72 Grains of H-1000 powder and Berger 180 Grain Hybrid Bullets
I load on an Redding Press with Hornady Custom Dies. RCBS Digital Powder Scale, RCBS Hand Primer
I use an Oehler Model 35P chronogroph
I haven't tried any different loads as my rifle shoots these so well.
Did you ever try the 168 grain bullets, just curious as to how they shot?
I am going to weigh all of my brass this weekend so I will get back to you next week with what I find.
Rick Richard
Well-Known Member
I have a bag of 100 which was provided with the custom I just recently purchased. Maybe I should weigh them also. However, I am reluctant to change anything since it will shoot 3 shots typically in the same hole at 100 yards with an average speed of 3005 fps (Magnetospeed). That is using 71 grains of H1000, 180 Hybrids and Federal 215 primers.
