7 lrm

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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: www.snipershide.com/shooting/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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[/img]

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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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Tag
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Eric7mmXPrivate
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Re: 7LRM Load Data
11/09/2014

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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

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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

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Anyone played with the Berger 195s yet?
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SonicCrackXFirst Sergeant
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Re: 7LRM Load Data
12/26/2015

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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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1518 posts this site
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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393 posts this site
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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1518 posts this site
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]

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).

 

[BurnOut]

Just got done putting together some more loads to try. I'm running pressure ladders on the Berger 195s and Sierra 197s using IMR 8133 (72.5-74.5 in half grain increments), IMR 7977 (68.5-71.0 in half grain increments), and Ramshot Magpro (68.0-70.0 in half grain increments). I'm also running a pressure ladder on the 162 ELD-X with IMR 8133 (74.0-76.0 in half grain increments).

I also did some more measuring using the Hornady OAL gauge, and have found that I must have been whacked out on goofballs or something when I took my last set of measurements. Current, triple-checked measurements are as follows: Base-to-ogive for Berger 195s is 2.736 (at the lands), for the Sierra 197s is 2.746 (at the lands), for the 162 ELD-Xs is 2.706 (at the lands), and for the 168 ABLR is 2.740 (at the lands). For this round of loads, the Bergers are .018 off the lands, the Sierras are .010 off the lands, while the ELD-Xs are .020 off the lands. At this point, I am too lazy to pull the Bergers and the ELD-Xs just to get them seated .008-.010 closer to the lands. For the purposes of pressure testing, I figure close enough is good enough.

I should note that I do find it interesting that the measurement for the 168 ABLR is .004 longer than the Berger 195s, though...

 

[BurnOut]

Well, my latest range trip got me some results; it looks like 8133 and 7977 are just not the solution that I am looking for when used in conjunction with Berger 195s and/or Sierra 197s. At 63 degrees ambient temp, I hit pressure (light/moderate "ejector" swipes) at 73.5 gr of 8133 under both the Berger (2932 FPS) and Sierra (2959 FPS) projectiles. Using 7977, I saw the Bergers at 2929 FPS and the Sierras at 2916 FPS over a load of 71.0 gr. While I didn't see pressure signs using this powder, I don't think that I'd be able to get another 70-80 FPS out of it without crossing the line. However, Magpro may be showing some promise under the Berger projectiles; 70.0 gr got me 2918 FPS; the Sierras unfortunately started showing some pressure signs around 69.0 gr (2881 FPS).

In any event, I was able to run 162 ELD-Xs over some 8133, and that seems to be a good match in terms of speed; 74.0 gr got me 3043 FPS, and it only went up from there (the highest charge I tried was 76.0, and saw 3118 FPS). For my purposes, I'm going to back down on this one a bit... 3k FPS is just dandy for me. I'll likely start trying to find a load that it likes around 73.8 or so.

 

[BurnOut]

Just loaded up a pressure ladder with the Berger 195s: 68.0-70.0 in half grain increments with RL26, and 77.0-79.0 in half grain increments with RL33. I'll post the results when I have them.

EDIT: got to the range today and got the following results (at 59 degrees ambient temp):

RL26
68.0 - 2911
68.5 - 2915
69.0 - 2936
69.5 - 2947
70.0 - 2966 (moderate ejector swipe)

RL33
77.0 - 2969
77.5 - 2927
78.0 - 2974
78.5 - 2990
79.0 - 3003 (faint ejector swipe)

I'm going to put together some loads at 78.5 of RL33 and perhaps moving up slightly from there to see if I can find one that will group for me. The research continues.

 

[Rmk9494]

Hows that 7 lrm treating u u stilling it. Hows barrel life. And have u tried necking down 375 ruger brass for it

 

[dukerugger25]

Posting info on load work ups for my rebarrelled 7LRM. Original barrel which lasted about 1200 rounds liked the 180gr Berger Hybrid best. Load was 69.7g H1000 @ 2962fps - 3.413" OAL. Would hold <0.5MOA out to 1000yds, until it didn't.

Data will be posted in 2 sets: Ladder during first 150 rounds, Final OCW after barrel sped up ~70fps

New Barrel - Proof 1:8, 26"
Brass: GW, Bullet: 180gr Berger Hybrid, Powder: H1000
OAL: 3.413" = 0.020" from lands

Charge (gr)	Round 1
69.0	2880
69.2	2902
69.4	2901
69.6	2926
69.8	2931
70.0	2943
70.2	2940
70.4	2942
70.6	2938
70.8	2966
71.0	2975
71.2	2980
71.4	3003
71.6	2998
71.8	3003

New Barrel - Proof 1:8, 26"
Brass: GW, Bullet: 180gr Hornady ELD-M, Powder: H1000
OAL: 3.390" = 0.025" from lands

Charge (gr)	ELDM's
69.4	2966
69.6	2958
69.8	2960
70.0	2985
70.2	2972
70.4	2991

***********************************************************************************************
Barrel after 150 rounds*************************************************************************
***********************************************************************************************
Brass: GW, Bullet: 180gr Berger Hybrid, Powder: H1000
OAL: 3.413" = 0.020" from lands
6 shots @ each charge weight

Charge	Avg
69.6	2965
69.7	2987
69.8	2990
69.9	2989

Brass: GW, Bullet: 180gr Hornady ELD-M, Powder: H1000
OAL: 3.390" = 0.025" from lands
6 shots @ each charge weight

Charge	Avg
69.6	2998
69.7	3009
69.8	3004
69.9	3018

***********************************************************************************************
Ladder with RL26******************************************************************************
***********************************************************************************************
Brass: GW, Bullet: 180gr Hornady ELD-M, Powder: RL26
OAL: 3.390" = 0.025" from lands
3 shots @ each charge weight

Charge (gr)	Round 1
65.4	2894
65.7	2917
66.0	2916
66.3	2924
66.6	2929
66.9	2959
67.2	2944
67.5	2959
67.8	2979
68.1	2988
68.4	3010
68.7	3012
69.0	3040

***********************************************************************************************
Landed on a load for the ELD-M's with H1000 @ 69.7gr, saving RL-26 for my PRC's.
Performed 2 OCW groups @ 200yds, averaged data below
***********************************************************************************************

OAL	RTO	Jump	Average	MOA
3.400	2.665	0.005	3005.667	1.5
3.390	2.655	0.015	3000	0.21
3.380	2.645	0.025	2995	0.4
3.370	2.635	0.035	2987	1.09
3.360	2.625	0.045	2990	0.75

I ended up settling on 3.385" OAL (0.020" jump) with the ELDM's, averaging 2997fps. Shot steel out to 1000yds last weekend - perfect!

The best load for the 180gr Berger Hybrids was 0.053" jump (3.380" OAL), averaging 2992fps with an SD of 3 over 20 shots, however i could not get anything better than a 0.89MOA group @ 200yrds.

Lesson: The barrel will tell you which bullet it likes!

 

[sodakhunter]

For all shooting 7lrm, gunwerks now has ADG made brass available on their website. It's pricey as hell, but will undoubtedly outperform the Hornady junk by a huge margin!

Thats a huge plus!! Ive had loose primer pockets after 2 firings on the Hornady stuff but I have them bout maxed out pressure wise.

 

[dukerugger25]

All the brass I loaded in April up above is toast in the primer pockets. About 130 lasted 4, 20 only 3 firings. I’ve still got 200 of the Hornady stuff, so won’t be trying the ADG just yet, but good to hear it lasts longer.

 

[acts238]

what is a 7LRM ? 7mm rem mag or ?

 

[fdkay]

@orkan are you still playing with this cartridge?
Now that Gunwerks has better brass, which neither ADG or Gunwerks will confirm is ADG brass, it is a whole lot better than the hornady brass.
I'm thinking of rebarreling my 7RM to this in order to shoot the 175-180 bullets a bit more efficiently.

 

[orkan]

@orkan are you still playing with this cartridge?
Now that Gunwerks has better brass, which neither ADG or Gunwerks will confirm is ADG brass, it is a whole lot better than the hornady brass.
I'm thinking of rebarreling my 7RM to this in order to shoot the 175-180 bullets a bit more efficiently.

Not much anymore. Although in some situations I still recommend it. Great cartridge, and the ADG brass is good to go.

It's just that with the Medium length Lone Peak Fuzion actions and the Hawkins Precision bottom metal... the short mags (basically all of them) are much more appealing to me. I'm going to be running a 7mm PRC Primal (7-6.5 PRC improved) very soon in one of those configs. With lapua 6.5PRC brass... boy it's compelling.


-----------

 

[Schw15]

I wonder why this never caught on. Seems like a great case. What is that you guys seem to like or hate about it?

 

[Steel head]

I wonder why this never caught on. Seems like a great case. What is that you guys seem to like or hate about it?

I always thought it was a neat concept.

 

[Schw15]

I always thought it was a neat concept.

Yeah I was looking at it great design and able to mag feed abs get great velocities. I know brass is harder to get but might be something to play with

 

[4O6shootist]

If you guys contact gunwerks they have a pile of once fired 7lrm adg made brass available. I'm now looking to find a reamer for my smith.

 

[fdkay]

If you guys contact gunwerks they have a pile of once fired 7lrm adg made brass available. I'm now looking to find a reamer for my smith.

I believe that Gunwerks will rent the reamer to you, at least they did at one time.

I know that they have a bad rep, but I believe they are where gunwerks gets their reamers.

7 mm LRM Custom Chamber Reamer - Pacific Tool and Gauge

7 mm Mauser Custom Chamber Reamer. Made in White City Oregon USA. Making Firearm Parts and Chamber Reamers Since 1957.

pacifictoolandgauge.com

 

[Schw15]

If you guys contact gunwerks they have a pile of once fired 7lrm adg made brass available. I'm now looking to find a reamer for my smith.

Did you find a reamer?

 

[4O6shootist]

Did you find a reamer?

Ordering one on Tuesday. I ordered 200x pcs gunwerks(adg made) lrm brass, their fl bushing dies and 317,316 bushings. I'm going to get some crucial dimensions to compare fired vs sized for spec'ing as well as loaded neck od. My smith is awesome, he's like tell me what you want and I'll order it. Yeah it'll take a while but oh well.
Its going on a bat vampire, ag alpine hunter and the bartlein carbon #13 8.7tw 26" blank I have in hand currently.
8.7 with my altitude 100% stabilizes all bergers from 175-190gr. I will not shoot 195s in this barrel. 180hyb at 3100 vs a 195 going 2980, not much different to 1k anyways

 

[Schw15]

Ordering one on Tuesday. I ordered 200x pcs gunwerks(adg made) lrm brass, their fl bushing dies and 317,316 bushings. I'm going to get some crucial dimensions to compare fired vs sized for spec'ing as well as loaded neck od. My smith is awesome, he's like tell me what you want and I'll order it. Yeah it'll take a while but oh well.
Its going on a bat vampire, ag alpine hunter and the bartlein carbon #13 8.7tw 26" blank I have in hand currently.
8.7 with my altitude 100% stabilizes all bergers from 175-190gr. I will not shoot 195s in this barrel. 180hyb at 3100 vs a 195 going 2980, not much different to 1k anyways

Is that there 1xfired brass or new from them? Where are you ordering the reamer from?

 

[4O6shootist]

Is that there 1xfired brass or new from them? Where are you ordering the reamer from?

Its 1x fired. I wanted the dimensions of fired vs sized to see where we need to make the reamer improvements at. I have a gen2 gunwerks print from my first lrm 5 years ago. The brass is just 300prc shortened up bit and necked down, that's why it has thicker than normal 7mm dimensions. There 0.200 line dimensions in the chamber is too tight in saami form in the 300/65 prcs. So i want to see how much the dies size the base of the cartridge. If it doesn't size it back to 529, we'll prob up the 200 line of the chamber to 535 vs 533 on the current prints.

 

[Schw15]

Its 1x fired. I wanted the dimensions of fired vs sized to see where we need to make the reamer improvements at. I have a gen2 gunwerks print from my first lrm 5 years ago. The brass is just 300prc shortened up bit and necked down, that's why it has thicker than normal 7mm dimensions. There 0.200 line dimensions in the chamber is too tight in saami form in the 300/65 prcs. So i want to see how much the dies size the base of the cartridge. If it doesn't size it back to 529, we'll prob up the 200 line of the chamber to 535 vs 533 on the current prints.

I have heard of the issues with the prc cases. Hopefully the 7lrm doesn't have that issue. Do they even sell new brass? I have a 7mm blank might try one as well but need to see about reamer not sure if gunwerks rent them or sells them

 

[4O6shootist]

I have heard of the issues with the prc cases. Hopefully the 7lrm doesn't have that issue. Do they even sell new brass? I have a 7mm blank might try one as well but need to see about reamer not sure if gunwerks rent them or sells them

I feel that since this case uses 300prc brass cups for production, it'll have same tight web issues as the parent brass. So we'll just spec the reamer larger and problem solved. My smith does EXCELLENT work, he'll have the reamer in April likely if you can wait that long. He'll prefit a lot of actions with proper tolerance. But some he will need the action.

 

[Schw15]

I feel that since this case uses 300prc brass cups for production, it'll have same tight web issues as the parent brass. So we'll just spec the reamer larger and problem solved. My smith does EXCELLENT work, he'll have the reamer in April likely if you can wait that long. He'll prefit a lot of actions with proper tolerance. But some he will need the action.

Does he do arc nucleus gen 2?

 

[4O6shootist]

Does he do arc nucleus gen 2?

Hes going to have my Archimedes in his hands approx 4 weeks time to measure. They share the same tenon as the Nuc. So yeah I don't see why not.

 

[Schw15]

Hes going to have my Archimedes in his hands approx 4 weeks time to measure. They share the same tenon as the Nuc. So yeah I don't see why not.

Oh nice. I hate that double click from tight chamber walls worst so hopefully it don't need it but I'm interested in results

 

[762 ULTRAMAGA]

Has anyone measured the H20 capacity with adg 7 lrm brass?

 

[4O6shootist]

Has anyone measured the H20 capacity with adg 7 lrm brass?

I believe mine was 86.5gr.

 

[762 ULTRAMAGA]

I believe mine was 86.5gr.

Thanks
And you hit 3100 with 180s from a 26" barrel?

 

[4O6shootist]

Thanks
And you hit 3100 with 180s from a 26" barrel?

Yes, but I'm running a bat action and an 1.250 tenon barrel, these will hide pressure over others. My chamber base is also 535, vs conventional 533, so my dies are sizing more in relationship to fitment delaying clickers from web growth(lessons learned from PRC cases).

 

[Boltgundriver]

My brother asked me to develop a load for his Gunwerks 7 LRM for an upcoming elk hunt. I'm getting pressure indications well below book performance for this cartridge. This rifle was purchased in 2015 and has about 80 rounds down the barrel. Using the factory recommended load I'm getting light extractor marks on the brass., this is at a speed of 2940.
I'm loading:
70.5 gr H1000
Gunwerks factory brass (shot once) I've closely inspected this brass and it doesn't appear to have the dimensional flaws that were present in the early production.
Berger VLD Hunting 180 gr.
Federal 215 primers
.020 jump
case shoulder set back .001

The SD in under 10 and I've tried Fed 215, Fed 210M and CCI 250 primers, all performed about the same although the Fed 215 are the fastest at 2940 and the CCI were the slowest at 2910. Still this is 200 FPS less than advertised.

I've been getting the "two in one hole and the third is an inch away" group (more horizontal than vertical). I expect this can be corrected with seating depth but I still don't know why I'm having to sacrifice so much speed. I should note that the ejector marks are light enough that they a just shinny spots, nothing you can feel. Am I being too sensitive to the pressure signs or is there a solution that would allow me to regain the speed and reduce pressure signs or at least not make them worse? I've spent some time reading every thread on this caliber I can find on the net and there are surprisingly few. Is this a caliber that just didn't catch on or did it not live up to the hipe?

 

[4O6shootist]

@Boltgundriver ia this Hornady brass or ADG? The Hornady stuff had very thick necks and needed a revised reamer. See if you can get a bullet to slip into the fired case mouth without much resistance. The lrm with Hornady brass never lived to its advertised speeds with reloaded brass, virgin brass handles more pressure/velocity first firing as it's forming to the chamber, once fireformed it now has less room to expand, increasing pressure. I still feel the velocity you're seeing is low. What is your barrel length?

 

[Boltgundriver]

The barrel is 26 inches. The brass looks OK as the neck thickness is .013 to .014 and the fired brass measures .318 at the neck. A bullet drops in easily after firing. This brass was bought in 2015 as loaded ammo from GW. I did find one box of brass that was bad. I started trying to set my shoulder bump and found that the shot brass measured 2.038 while the new loaded ammo from GW measured 2.048 to 2.050. Now, how is it that fired brass is .012 shorter than new brass? The other boxes of fired brass measured 2.052 to 2.053. I may have to just accept the marks on the brass and just plan to only get a few firings out of the brass.

Clearly, this gun doesn't get used a lot but I'm trying to get a hunting bullet for it that outperforms the Berger 180 Hybrid. He shot a deer through the lungs at about 120 yards a couple years ago and the hybrid punched through the animal without expanding. We found the animal about a 100 yards from where it was shot. We didn't find a single drop of blood. Even where it fell, there was no blood. Bullet availability is limiting my options so I'm trying the Berger 180 VLD hunter. He called GW and asked what they recommend. Their answer is to shoot the animal through the shoulder if its closer than 400 yards. I can see where that works and if I'm looking at a 400 inch bull I would give that serious consideration. But I really hate the idea of taking an animal and then throwing away half of it because its bloodshot.

 

[4O6shootist]

180hyb have been very consistent in expansion for me, surprising yours penciled. 180 eldm will do well, load them 10k off touch and work up from 68gr in 0.5gr steps. I'm using adg brass with 71.5gr H1000 sending 180s at 3020 fps Bat action, 24" hawkhill 8.5tw barrel.

 

[Boltgundriver]

Thanks for the ideas. I'll try a work-up as you recommended. I read in one post that Retumbo was giving better speeds without pressure signs. Of course it's hard to ignore SD's under 10. Fortunately, I've got a few months to work this out. Any excuse to go to the range, right? Thanks
Gregg