7LRM Load Data

[orkan]

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?

 

[Aflac]

Great info, now I just need to get my hands on some h1000......and a barrel, brass, dies, and bullets.....but in the researching I've been doing since you suggested this round to me last week it seems everyone is using h1000.

 

[orkan]

I'm really looking forward to giving some faster powders a try. I want more zoom out of the 162's!

 

[Saito]

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?

Travis got my 28" Bartlien barreled LRM finished a month ago and I got it all broke in and now have 100 rounds down it. H1000 and a 180 VLD is my choice for a load. Actually got the data from the only other guy I know who has one and 72.3grns is giving me 3170fps with the 180. I started at 72grns(buddy's load)and that was giving me 3077fps. Travis also built this other rifle with the same reamer(and I'm assuming yours was too). I'll look it up and give you some AOL and ogive measurements. I was having hell with the wind last time I was home(and gunwerks took a month to get me my brass because they didn't have dies when I ordered everything), so the only group I was able to shoot was back in the trees, looking through some vegetation and I managed to put 8rds into about .75". I went with the fastest twist I could find at 8.4 and had Travis finish it a the longest length possible. He did a fantastic job, as usual.

I was actually going to send you a pic of the finished project a couple days ago, but I don't seem to have your # any more. PM me

 

[KYpatriot]

I am shooting a straight 7RM with 180 hybrids, seated long to 3.55 oal, can't remember the base to ogive length. Retumbo is giving me 3050 out of 26" Bartlein, tiny groups at 200 but the ES is up as high as 50 so I'm not happy with it yet. I get smoked necks with Retumbo even when I got the pressure up to where I had slight ejector marks. Not sure what that means really. Thoughts?

Orkan seems like you should be seeing more velocity than that with Retumbo before seeing pressure, were you getting similar numbers to H1000 or was it faster? I would think it would do better in the 7 Lrm then it would my rem mag.

 

[orkan]

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.

 

[Mr_Happyface]

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.

This was my experience as well.

I was getting shit for ES with H1000, Retumbo was much better (although still not good), carbon was getting on the neck though.

Switched to mag primers and ES was all over the map - gained about 100fps though. Sticking with CCI200s.


This was during the very initial stages of working up a load.

Also - I'm not in love with the Hornady brass and I hope someone else makes it as well one day - although with it being a proprietary cartridge I'm not holding my breath.

 

[milo 2.0]

I've only handled this case, don't own one. But to me, being so overbore, N570 or RL 33 seem a logical choice for 180's, and those 2 especially when the elusive 195gr hits the market.

 

[Aflac]

Greg,
You don't happen to have the information needed to add this case into quickload do you? I like to use the optimal barrel time method for loading and that means spending some quality time in quickload prior to building any rounds.

 

[Mr_Happyface]

I'm looking for the same thing.

 

[orkan]

Nope, I don't have the specs for quickload.

 

[orkan]

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.

 

[milo 2.0]

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.

Not trying to be a jerk, but the numbers you're posting reflect what most of us get out of a 7mm saum. Without paying for propriety priced components. You have me baffled as to what smoked necks has to do with performance? A slower powder will not seal the neck as quickly as a fast powder, but as long as it's not coming down the case body, it's still working fine.
Your case is about as overbore as they come, and until you get into slower powders, you're never going to realize the potential of the case.
.375 necked to .274

 

[orkan]

Feel free to start a new thread somewhere about 7LRM vs 7SAUM. Another for what smoked necks means. If you wish, another about 7LRM being overbore. This thread is about 7LRM load data.

 

[wapiti16b]

Orkan & Saito , who did the work on your rifles ? , I'm a little curious about a rifle of my own . Also what kind of barrel life do you expect out of the 7LRM ?

 

[orkan]

TS Customs in Miller, SD. Travis is one of the most talented and easy to work with smiths I've encountered. www.tscustom.com

I expect to get 2000-2500rnds out of a barrel. Though I honestly have no clue, as I've not shot one out yet. Matter of fact, I haven't heard from anyone that has enough rounds through their LRM to know.

 

[wapiti16b]

Thanks , this is a cartridge I'm considering for a hunting rifle re-barrel .

 

[dworrel]

What about Ramshot Magnum? Comparable burn rate to H1000.

Might get some more velocity as well.

Also might try PP4000 MR.

Waiting to get my TS Customs 7LRM barrel from Primal Rights currently. Great service. Very eager to try this out. Also have a couple 6.5 SAUMs.

 

[orkan]

I haven't tested ramshot magnum. Give it a go and report back!

Your 7LRM kit left today and is on its way!

 

[Aflac]

Have you tried any longer barrels than 26? Would there be a benefit? Could I talk you into posting the measurements of the case that I would need to load the case in quickload? I'd like to run some numbers on different barrel lengths before I decide what to get.

 

[orkan]

30" produces around 100-150fps over a 26" barrel. That's pretty substantial. Still plenty of room there.

What measurements do you need?

 

[Aflac]

I don't remember offhand, we relocated to albuquerque for a few weeks so my wife could deliver at a good hospital and my quickload is back at home. I'll post what I need when I get home.

 

[dworrel]

So... I noticed that the 190 Matrix (.673), 180 Berger Hybrid (.674) , and the 175 Nosler ABLR (.672) all have essentially the same BC.

I assume you can push the ABLR a little faster, but the Matrix bullets have more mass.

Any opinions on a "best" bullet for this caliber? Going on an elk hunt this fall.

 

[orkan]

Any opinions on a "best" bullet for this caliber? Going on an elk hunt this fall.

Boy that's a hard question. I'm there myself right now. The ABLR's are expensive! $10 per 100 more than the bergers, and have 3 times the weight variation. I have no experience shooting animals with either bullet, so I don't dare say which performs better. They both seem to shoot well. The bergers are likely the easiest to find.

If I were forced to pick one right now, it would probably be the 180 Berger VLD Hunting just based on cost and availability.

Once the weather breaks, I'll be doing some OCW's with 162Amax and 4831SC. If I can get the speed up, it will be hard to look past them for an all-around bullet in 7LRM.

 

[dworrel]

Orkan, one thought on the "smoked necks" discussion. I remember a discussion I had with Josh at Copper Creek when he did load development for me on a 7WSM when I was short on time. He told me he had gone to Fed 215 GMM Match primers for the WSM/SAUM and larger magnum calibers for full ignition/consistency on slower burning powders. I wonder if a primer change would eliminate the "smoked necks"?

That being said, there seems to be a pretty strong consensus that H1000 is the best powder for this caliber.

 

[orkan]

I thought about that as well, just haven't tested it. I had to switch to 215's in 375CT due to severe hang fires with CCI250. Clearly there's more "fire" going on with the 215's. You may just be onto something there.

 

[orkan]

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.

 

[Mr_Happyface]

I was having the same issue with the LRM, best extreme spread I could get was 30FPS. (I say was because I'm away from home after only a few days of working up a load)

I've only handloaded for .308 up to this point. What is an acceptable ES for a cartridge of this size?

 

[orkan]

With virgin horandy brass? If I get less than 40-50fps I'd be pretty happy. On once fired I see no reason why a guy couldn't get down to less than 20'ish. Single digit ES is extremely hard to achieve with anything, and chronographs are often VERY misleading. I've had many shooters claiming single digit ES come and push some rounds through my PVM only to find they weren't single digit at all, or even close. My PVM is pretty darn accurate, yet I still don't trust it much either. Bottom line: I don't let ES decide my load. I let my targets decide my load. I've had loads that had a 50-60fps + ES that shot 6" at 1000yds repeatably.

 

[Mr_Happyface]

Rgr, thanks for the advice.

I was averaging 100ES or so on some of the loads I tried (Retumbo and H1000) but got it down to 30 with Retumbo. Velocities were about the same, with Retumbo obviously taking more powder but showing less pressure at the same velocity as H1000. Carbon on the necks though.


Looking to work up a load using a powder that'll be pretty temp stable and it looked to me like these would be the powders to go with.

 

[Aflac]

Greg, if i did this properly included should be the screen shots from quickload on what data is needed to build the case to run some numbers.

the numbers already in are just what quick load put in. so give them zero weight.

 

[Mr_Happyface]

I hope someone can provide this info. I don't know how to take a lot of these measurements or else I'd do it.

 

[orkan]

 

[Aflac]

Thanks Greg, do you by chance know the pmax? I think that's the only info not on your drawings

 

[Aflac]

Also need maximum cartridge length if you have that available.
and caliber groove, and bore, number of grooves

 

[Aflac]

ok i should have figured out everything i needed before posting, but also case weight, i think that will finish it out and then i will have all the data, once i get that i will post the quickload file if i can.

 

[tho98027]

What's the h2o case capacity of this case?


Sent from my iPhone using Tapatalk

 

[Mr_Happyface]

You guys are awesome, I wish I was home with my notes so I could contribute to this.

The case weights I had were all over the map - there was easily a 10-15 gr spread between the 400 cases I ordered. I'll post my numbers in a few days.

 

[orkan]

The case weights I had were all over the map - there was easily a 10-15 gr spread between the 400 cases I ordered. I'll post my numbers in a few days.

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.

 

[Aflac]

I figure that the grooves of the barrel are probably the same as any other 7mm, and all 7mm in quickload had the same info for that so I just used that. So a good oal, pmax and case weight is all I need to start running numbers.

 

[Saito]

I popped 4 primers at the cup last month and I'm sure that brass is toast. It's too soft from the factory and I'm going to send all 400rds(297 of which is fired) back to Gunwerks and hopefully get some better brass from them. I think 1.34 a round is a premium price and it's not premium brass. I've never had primers blow out before. It smoked my ejector and I ended up having to fish the empties out with my finger during the last stage of the cup.

I like the round and all, but I wish better brass was available. I hope Gunwerks steps up and gives me some decent brass after I send my crap back.

 

[orkan]

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

No idea on where to start with pressure. However, as a modern magnum cartridge, I would bet it would be close to others with similar capacity.

 

[orkan]

I popped 4 primers at the cup last month and I'm sure that brass is toast. It's too soft from the factory and I'm going to send all 400rds(297 of which is fired) back to Gunwerks and hopefully get some better brass from them. I think 1.34 a round is a premium price and it's not premium brass. I've never had primers blow out before. It smoked my ejector and I ended up having to fish the empties out with my finger during the last stage of the cup.

I like the round and all, but I wish better brass was available. I hope Gunwerks steps up and gives me some decent brass after I send my crap back.

What kind of load were you running?

 

[Saito]

Same load as above. 72.3 grains of H1000 with a 180 VLD at 3170fps. H1000 isn't supposed to be temp sensitive, but apparently it was too hot or the brass was too soft.

 

[orkan]

In my experience it isn't that temp sensitive, but 72gr has been pretty warm in everything I've tried it in, so 72.3 would be likely to produce some pressure no doubt, and 3170 is hauling some serious ass. Where did you find pressure when you were working up?

 

[Aflac]

https://drive.google.com/file/d/0B4EFWY3aPaRORWFhbkJacGR5c2s/edit?usp=sharing

If i did this properly this should be the file to the quickload file i made for this...if someone who uses quickload could sanity check it for me that would be great. The other 7mm magnums all had pmaxes between about 60000 and 64000 so i used 62000. When i put everything and adjusted the burn rate to match your muzzle velocity Im getting a pmas of 61460 with 72 grs, so under that max pressure, 73 gr give 64498 which is over, but not by a lot, and 74 is showing 67698 so over pretty significantly (this was with the 168 berger load in the first post.)

the burn rate factor i used was 0.39. if i used the defaul 0.366 it did not show any overpressure until 75 gr and was 100fps slower. so for your lot of h1000 at least it looks like it has a little higher burn rate.

 

[Saito]

In my experience it isn't that temp sensitive, but 72gr has been pretty warm in everything I've tried it in, so 72.3 would be likely to produce some pressure no doubt, and 3170 is hauling some serious ass. Where did you find pressure when you were working up?

I didn't have time to work up a load. I used Rob F's load and you'd think I'd know better. I really should have just shot my TSC .300WM this yr at the match. I also wasn't getting the velocity he reportedly did with the data he gave me. Also should have just went with the 3077fps and been happy with that. But I don't listen to my gut instinct sometimes. I had 4 days to get my brass prepped(trimming a shitload off), load & test a few and get the rifle broke in. All while f'n the wind ripped everyday & I drove back to my home state of WY after work to get a good solid zero before the match. It's a good thing I did.

 

[Brentc]

Get some RL33 if you can find it. I'm getting outstanding results with my 7RM with 180 VLDs at 3140 fps. You'll have to test temp sensitivity in your load and rifle.

 

[orkan]

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.

 

[Saito]

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.

I agree. I stopped using RL powders when I found out about how sensitive they were and it sucks because I had a good load for a 190 SMK in the .300WM. Didn't ever have an issue, just didn't like the thought of it.

Anyhow, if I could find some N570 and some 195s, then I'd be set I'll be working up a load with both Retumbo and H1000(possibly some Ramshot powder too) in the near future.