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orkan

XFirst Sergeant
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7LRM Load Data
10/07/2014 Last edited 10/07/2014 by orkan
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Ported my posts from old site. Still meaningful discussion in the old thread: forum.snipershide.com/snipers-hide-reloading/250541-7lrm-load-data.html

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I've been spending a lot of time with 7LRM lately. Fun cartridge, and pretty easy to work with.

For all loads I am using CCI250 and Hornady brass sourced at gunwerks. The brass is a bit on the soft side, as is often the case with hornady. I most certainly hope winchester picks up the 7LRM or even Lapua. Here's some loads that are working well. Testing was done at 100yds. Barrel is a TS Customs 26" 9 twist DTA barrel spun from a Benchmark blank.

175ABLR @ 2.695 to ogive, 72gr H1000 - .412" - 3060fps
Signs of pressure at 73gr, wicked pressure at 74gr.

162AMAX @ 2.665 to ogive, 72gr H1000 - .310" - 3080fps
Signs of pressure at 73gr, wicked pressure at 74gr.

Berger 168VLD Hunting @ 2.665 to ogive, 72gr H1000 - .288" - 3060fps
Signs of pressure at 73gr, wicked pressure at 74gr.

I then did additional testing with Retumbo on each of the above bullets. The load crossed over almost identically, with 71.5gr producing the best accuracy with the lighter bullets, and 72gr producing the best results with 175ABLR, though it did show a bit of pressure. Also, the pressure curve is definitely out of whack with Retumbo on these bullets in 7LRM, as the necks were smoked pretty good, yet pushing farther showed significant pressure. Though I'd consider 68gr to be a decent starting load with Retumbo or H1000.

Usually when you drop some bullet weight, you can stack in a bit more powder and ratchet up the velocity... but that is not what I'm seeing here with H1000 or Retumbo. Then don't forget the smoked necks with Retumbo. This leads me to believe that that H1000 is the best powder to use with the 180gr-class bullets, but the lighter bullets in the 162gr range might benefit from a faster powder such as 4831SC or maybe even 4350. I'd love to hear educated thoughts in regard to this. Though for now it is clear that the 7LRM H1000 combo is well suited to the heavies! Berger 195 anyone?
Perhaps Retumbo would come into its own with that bullet if/when it hits the shelves.

Through talking with another shooter, it is also clear that the 7LRM has a lot of potential with longer barrels. We're seeing markedly higher velocities all the way out to 30" of barrel. Haven't tested anything longer than that yet. Berger 180's on top of 72gr of H1000 is producing just below 3200fps from the 30" tube with very mild pressure showing as a result of the soft brass.

I got a hold of some 190matrix, 175SMK, and 180 Berger's to try out next. I'll try to keep you posted. What's everyone else got going on in 7LRM?

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Velocity with retumbo was right there with H1000. No real increase.

I too had smoked necks with retumbo regardless of pressure. That kind of tells me its a bit too slow even with 175-180's. At the very least, it tells me that retumbo isn't necessarily the right powder for this cartridge. H1000 seemed more forgiving all around.

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Had another good day for load development today, finally.

190MB (matrix ballistics
2.700 to ogive
slight pressure at 70gr H1000, found a node at 69.5gr
0.420" and 2910fps.

175SMK
2.700 to ogive
slight pressure at 72.5gr H1000, found node at 71.5gr
0.285" and 3025fps

Thus far it looks like just about any of the contenders in the 7mm bullet arena will work well with this cartridge. Clearly there is a benefit to running the heavier pills when using H1000.

I did try the 190 Matrix with Retumbo to see if the smoked necks would be solved with a heavier bullet, and it wasn't. I ran a pressure ladder from 65gr to 72gr, and at no point did the necks clean up. It's very clear to me at this point that Retumbo is simply not a good choice of powder for this cartridge, with the bullets we currently have available. In case you were wondering, 72gr of Retumbo or H1000 behind the matrix 190 is VERY hot.

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Got some H4831SC tested today behind 162Amax.

162AMAX @ 2.665 to ogive, 66.5gr H4831SC - 3040fps
Signs of pressure starting at 68gr, wicked pressure at 70gr.

67gr - 3050fps, 67.5gr - 3060fps, but ES was all over the place on both. The 66.5gr load was about a 20fps ES and shot well enough.

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OAL with a 175gr ABLR is 3.375" and an average case weight is about 260gr.

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redd0311

XGunny Sergeant
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Re: 7LRM Load Data
11/04/2014
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Eric7mmXPrivate
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Re: 7LRM Load Data
11/09/2014
[HR][/HR]I had a 7LRM built by Jon Beanland earlier this year with the following components:
Stiller Tac300 lefty
Krieger Barrel @ 26" 1-9 twist
I sent the Gunwerks reamer back to PTG and had them regrind the neck to .317 to allow me to turn my necks down to achieve more consistency in my brass. I turn the brass to .313 and have a .314 loaded neck diameter which gives me .003 clearance.

My load is federal 215M with 70.0gr H1000 shooting the 180 hybrid. Velocity is 3020fps.
This load is extremely accurate in my rifle with groups less than .25 MOA @ 200. Even at extended ranges out to 940 yards this load still holds .5 MOA accuracy. With this load I can expect 4+ firings with the same brass.

I experienced pressure when using 70.5 grains of H1000, the bolt lift is a little heavy and there are noticeable ejector marks, but the primers are not flattened so it is right on the verge of being too much.

The Gunwerks claim to 3100 fps does not hold up without pressure be careful when developing loads!
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dworrelXSergeant
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Re: 7LRM Load Data
11/30/2014
[HR][/HR]7LRM 26" barrel for DTA from TS Customs.
Berger 180 Hybrid
Tula LRM Primer
71.0 Gr H1000. Primers flat.
Extractor marks at 71.6gr. Blown primer at 72.0 gr.
~3050 fps - seems to be gaining some speed as barrel breaks in.
worked up from 68.0 - 71.0 grains - all loads were ½ moa or better.

Shot an elk at 525yds with this load this year - DRT.
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Griffith187XPrivate
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Re: 7LRM Load Data
03/08/2015
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Hi Guys this is my first post on this forum I would like to know where you guys are located at. Im also interested in the 7lrm. I plan on going this route but am doing all of my research first I do want a big 7 but not sure who I will let do the gun smithing. I plan on using a bighorn action though. I appreciate all the info here on this site



Thanks and I am Located in Fort Lupton Colorado

Will



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ColtstersXSergeant
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Re: 7LRM Load Data
03/29/2015
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My 7LRM build should be complete at Elkhorn Precision soon, excited to see what she is capable of with 180Hybrid. Thinking about trying Tula Magnum primers instead of 215M, will depend on what I can get my hands on first.

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wapiti16bXGunny Sergeant
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Re: 7LRM Load Data
06/14/2015
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What brass options if any are available at this time ?

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ColtstersXSergeant
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387 posts this site
Re: 7LRM Load Data
07/02/2015
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Hornady makes the brass for Gunwerks. I got mine from Primal Rights, Greg was extremely helpful with all my 7LRM questions.

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mkollman74XFirst Sergeant
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Re: 7LRM Load Data
10/06/2015
[HR][/HR]Anyone played with the Berger 195s yet?
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SonicCrackXFirst Sergeant
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Re: 7LRM Load Data
12/26/2015
[HR][/HR]What is everyone getting for brass life? Got that far yet?
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ColtstersXSergeant
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387 posts this site
Re: 7LRM Load Data
03/20/2016
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mkollman74 wrote: Any updates on load data? Anyone have experience with the Berger 195s?​
^^^^This....also very interested in 175ELD-X

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mkollman74XFirst Sergeant
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Re: 7LRM Load Data
06/16/2016
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Berger 195s anyone?

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ColtstersXSergeant
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387 posts this site
Re: 7LRM Load Data
08/21/2016
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Finally found some local CCI #250 primers so now all I need is dies. Forster says they aren't doing custom dies right now so I'm thinking Whidden custom set. Any better recommendations?

Have plenty of brass and H1000 so once I get some dies I will see if 180Hybrid or 175ELDX works best.

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mkollman74XFirst Sergeant
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Re: 7LRM Load Data
09/09/2016 Last edited 09/17/2016 by mkollman74
(1 vote)
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7 Long Range Magnum
26" Bartlein 8 Twist Barrel
H1000, Winchester LR Magnum Primers
Hornady Properly Headstamped Brass
3.4" COAL

Berger 195 EOL Hunting Hybrids

Velocities listed are the average of two rounds fired

66.0 - 2681
66.5 - 2758
67.0 - 2798
67.5 - 2796
68.0 - 2816
68.5 - 2830
69.0 - 2856
69.5 - 2860
70.0 - 2881
70.2 - 2898
70.4 - 2909
70.6 - 2908
70.8 - Did Not Read (I think I forgot to arm the LabRadar... )
71.0 - 2944
71.2 - Did Not Read
71.4 - 2927

As you'll notice there are a few spots where the velocities seem to have plateaued. I do not know exactly what to make of this. I was trying to increase powder weight in small enough increments to be safe, but I may have gone too small. A 0.2 grain increase in the 70 grain range is only 2 to 3/10ths of a percent. Additionally, we suspected the WLRM primers may not be consistently igniting the large powder column.
So, back to the reloading room to try again with some CCI 250s. The data:
7 Long Range Magnum
26" Bartlein 8 Twist Barrel
H1000, CCI 250 Primers
Hornady Properly Headstamped Brass
3.4" COAL

Berger 195 EOL Hunting Hybrids

Velocities listed are the average of two rounds fired

70.4 - 2906
70.6 - 2903
70.8 - No Read
71.0 - 2925
71.2 - 2960
71.4 - 2953
71.6 - 2970
71.8 - 2959
72.0 - 2981

Of note, the first shot at 72.0 registered at 3004fps. I was hoping to get to 3000fps with this combo - or at least curious as to whether it could be done. I think the answer is yes, but not advisable to do so. Right around 71.6 I noticed the bolt starting to get a tad sticky. As I kept moving up in charge weight, I noticed some ejector marks as well. I do believe that I can get this combo to run around 2950 reliably with good accuracy. I will focus my OCW efforts with those goals in mind.

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SonicCrackXFirst Sergeant
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Re: 7LRM Load Data
09/17/2016
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Wild guess that your data ^^^^^ is for the 195's?

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mkollman74XFirst Sergeant
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Re: 7LRM Load Data
09/17/2016
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SonicCrack wrote:
Wild guess that your data ^^^^^ is for the 195's?​
Shucks... Looks like I need to fix my post. Yes, 195s.

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MachoKingXSergeant
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Re: 7LRM Load Data
12/30/2016
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I need this in my life. ~3000 with the 195's is nothing to sneeze at, with the same amount of powder as I use to push 162's in a 7 Mag.

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mkollman74XFirst Sergeant
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Re: 7LRM Load Data
12/30/2016
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MachoKing wrote:
I need this in my life. ~3000 with the 195's is nothing to sneeze at, with the same amount of powder as I use to push 162's in a 7 Mag.​
I ended up backing off to 70.2 of H1000. The barrel picked up some speed after breaking in, and I am getting 2950 with the 195s with that load

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gregsjtXSergeant
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Re: 7LRM Load Data
01/02/2017
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What is the deal with the newer brass for the LRM? Is it really better than the older stuff, if yes how much and how do we get our hands on the better brass and how do we tell which brass is newer / better?

Thanks,
 

BurnOut

DDOJSIOC
Nov 24, 2013
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Dallas
#2
Starting some experiments with 7LRM, IMR 8133, and the Berger 195s. At this point, I'm thinking that this powder might be too bulky for the application, but we'll see. I am starting off using Hodgdon's charge recommendations for the 7mm Wby Mag running 180 gr VLDs, so there's no telling where I'll end up. I'll say this, though... a charge of 77 gr is moderately compressed at an OAL of 3.467 (2.719 base-to-ogive, which is .009 off the lands in my barrel).

I'll update this thread with results once I get to the range. All information will be gathered from my rifle, which is wearing a 26" 8-twist K&P cut and installed by LRI.

Update - Got to the range with some of my reloads; loaded up some 162 ELD-Xs with 66.5 gr of H4831SC and got right around 3000 FPS average in 95 degree heat with the projectile .010 off the lands (base-to-ogive measurement is 2.686, COAL is 3.354). The IMR 8133 loads were a little, uh, warm. I hit 3054 FPS with a Berger 195 .009 off the lands (base-to-ogive is 2.719, COAL is 3.467) and a charge of 75.0 gr, and with a Sierra 197 I was dead nuts on 3000 FPS with the projectile .010 off the lands (base-to-ogive is 2.724, COAL is 3.520). Both exhibited sticky bolt lift and serious ejector swipes. Unfortunately, those were the lightest 8133 loads I had made up, so I'll be backing down from there. I was hoping that 8133 would be good for another 50-75 FPS over H1000 with the heavy projectiles, but it doesn't look like that's the situation (without going over pressure).
 
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