7LRM Load Data

[Brentc]

Lets not clutter up this thread with rem mag data please. It's about 7LRM. Unless you have first hand experience with that powder in 7LRM? 7RM and 7LRM are two completely different animals. You need to add a solid 5gr to 7RM load data to get in the ball park on 7LRM.

That said, every RL powder I've tested has been very temp sensitive. I have no reason to believe it would be different in 7LRM.

Hey man, that's fine. I was just offering something up that might help boost performance in your 26" barrel. The RL powders can be temp sensitive, however, sometimes they're not. In my application I have a 20 fps variance over an 80* temp spread. Not even enough to worry about.

 

[Darin Acklin]

I literally just became a snipershide member after seeing this thread. This may be the best meat and potatoes conversation I've seen on the LRM so far.

Gunwerks built my rifle and I received it in April. Their work is wonderful and I couldn't be any happier with my first custom build.

Has anyone on here tested anything at any extended distances yet? I started out with the Barnes 168 LRX and used data provided to me by Gunwerks (70.0gr Retumbo, 215GMM primer, and 3.320 OAL) I got some truly impressive 100yd groups with that load but my chronograph recorded ES of 114fps and at 1000 yards it showed. I don't believe I had a group under 15" @ 1000(Always Vertical). I have tried Accubond LR's (168 and 175), Barnes 168 LRX, and 150 Barnes TTSX. The 150 TTSX with 75.0gr of Retumbo and .070" off the lands was the only load I have developed that has been consistent. Velocity is right around 3200fps. Extreme spreads according to the chrony are around 25fps and I have two 7" groups at 1000yds. Definitely not the bullet I wanted to shoot out of this rifle but at least I have the load in my pocket in case nothing else works out before my mule deer hunt in September. I have tried H1000 as well with the ABLR and LRX bullets and have gotten essentially the same results as Retumbo. (Also noticed the smoked necks as well with both powders) I haven't weight sorted any brass yet, but from what I've read on here and other forums it sounds like a worthwhile effort as there seem to be some issues there.

I guess I really didn't introduce myself but my screen name is my real name and I'm from Greene County, PA. Howdy to you all and I look forward to some great conversations with other LR shooters!

 

[dworrel]

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?

Orkan,

I recently purchased a 7 LRM barrel from you for my DTA made by TS Customs. Fit and finish are excellent. Service was great.

Anyway you could post your OAL as well as your length to ogive for bullets with this round. That number seems to vary from comparator to comparator. I went to do some load development and got high pressure signs with starting loads. I usually use the Hornady OAL comparator with a threaded case to determine my max lengths. They don't have these that I am aware of for the 7 LRM.

I determined my length to lands with a Berger 180VLD by seating a bullet multiple times until it would slide when chambered in the gun. I would assume this is slightly jammed into lands, but still extracts. I re-checked my loads and was inadvertently jammed.


These are the numbers I got with all the 7mm bullets I have (using above method).

Hornady 162 AMAX:
Max length to ogive: 2.685"
Max OAL: 3.391"

Berger 168VLD:
Max length to ogive: 2.692"
Max OAL: 3.393"

Sierra 175MK
Max length to ogive: 2.730"
Max OAL: 3.376"

Berger 180VLD:
Max length to ogive: 2.733"
Max OAL: 3.438"

Berger 180 Hybrid:
Max length to ogive: 2.730"
Max OAL: 3.469"

 

[Mr_Happyface]

Brass is certainly the limiting factor in this cartridge thus far. Hornady can make good brass, but I've experienced my share of not-so-good brass from them.

Alright, I'm back home and working up a load.

The quickload specs here have been pretty helpful.

Tried running the brass through my Giraud trimmer and this is another time were I'm realizing how bad the brass sucks. Inconsistencies in body and neck thickness (and I'm now uniforming necks) are causing a decent amount of runout in my sized cases. The Giraud is trimming pretty heavily on one side and lightly on the other. Doesn't really give me a good feeling, and it's not a problem I ever had with Lapua.

I'm really hoping we can get another manufacturer to get in the game, Or has anyone looked into creating their own based off of the LRM's parent case?


Also, to add to the above; I have 3.462" OAL to lands with 180 Hybrids.


What primers are you all using? I've been using CCI 200s, tried Fed 215s but the ES was bananas.

 

[orkan]

Orkan,

I recently purchased a 7 LRM barrel from you for my DTA made by TS Customs. Fit and finish are excellent. Service was great.

Anyway you could post your OAL as well as your length to ogive for bullets with this round. That number seems to vary from comparator to comparator. I went to do some load development and got high pressure signs with starting loads. I usually use the Hornady OAL comparator with a threaded case to determine my max lengths. They don't have these that I am aware of for the 7 LRM.

I determined my length to lands with a Berger 180VLD by seating a bullet multiple times until it would slide when chambered in the gun. I would assume this is slightly jammed into lands, but still extracts. I re-checked my loads and was inadvertently jammed.


These are the numbers I got with all the 7mm bullets I have (using above method).

Hornady 162 AMAX:
Max length to ogive: 2.685"
Max OAL: 3.391"

Berger 168VLD:
Max length to ogive: 2.692"
Max OAL: 3.393"

Sierra 175MK
Max length to ogive: 2.730"
Max OAL: 3.376"

Berger 180VLD:
Max length to ogive: 2.733"
Max OAL: 3.438"

Berger 180 Hybrid:
Max length to ogive: 2.730"
Max OAL: 3.469"

Dworrel, my numbers were meant as a reference only, as you are absolutely correct that comparators can throw different numbers. I was 10 thousandths off the lands on all the data I've posted thus far. I'd measure your chamber with your OAL tool to ogive of the bullet you are loading for. Then back up 10 thou and give it a go. We will have modified cases for sale soon.

OAL varies from bullet to bullet severely. What bullet specifically are you looking for OAL on? You can always slot the neck on a case for a bullet to press-fit, and chamber it to find your length.

What primers are you all using? I've been using CCI 200s, tried Fed 215s but the ES was bananas.

I'm using CCI-250.

 

[dworrel]

I'm just trying to collaborate on data. As you see above from Mr Happyface post, chambers can vary a little bit as well.

Just trying to share all the data we can to maximize what we all get out of this cartridge. Hoping to get to the range later this week to develop loads as well.

If you were 0.010" off the lands, then there is a difference between our chambers (I assume). Not sure how you go about determining your distance to lands.

appreciate the input.

 

[Roger Moua]

Anyone load the 168 barnes with h1000 and fed210 primers? What jump are you guys at? I know it starts off .050 but just curious. Using adg brass 24 inch barrel