7LRM (Long Range Magnum) - Pic & Info thread

[BRNG525]

Wow I weighed my brass last night and from a bag of 100 brand new pieces. I didn't have more than six pieces that were the exact same weight. I don't know what the tolerances is or honestly what I should even be looking for but the weight went from 257.7 to 265.1 grains. Roughly half of the bag was within .5 grains of 260.0. Would somebody out there with more smarts than me please let me know what the tolerance should be on brass.

Is within one grain good, bad, terrible, doesn't make any difference????? I always thought it was the capacity of the case but I guess if they weigh more maybe it can change the pressure.

Looking forward to some schooling here..............

 

[agentcooper]

That's right in line with my weights with the last batch of 200 I ordered from Gunwerks. I believe you are correct, it is case capacity that makes the difference but, if all external dimensions are the same and one piece of brass weighs more than another, then that material has to go somewhere......effecting the inside of the case and either reducing or increasing capacity if it is heavier or lighter respectively. I know that I loaded up a few rounds at all three weight nodes and I achieved nearly 150fps in velocity variation. I can also tell you this, if you load until you are getting a slight extractor mark on the brass with the 257grn is weight and then put that same powder charge into a 265grn case, the brass is pretty soft and you will blow it out around the primer pocket.

Completely unacceptable for what I need out of that rifle and that is what led me to weight sort. I have a bit of a small fortune in brass and neck turning tools now though and very little usable brass to show for it. lol All will be forgiven in my book as soon as quality brass is abundant! I just know I am done playing with it for now and have to accept the multiple small lots of brass that I have to work with. I have spent so much in time, components, and money that it almost burnt me out on shooting for a little bit. Who thought that could be possible????

Perhaps one very simple solution is Gunwerks or Hornady can very easily weight sort the brass and you could buy it in lots that way. I really don't care what they weigh just as long as they are all the same and usable. No one likes two minutes of vertical in their 1000yd groups!

 

[BRNG525]

gun)agent cooper,
I couldn't agree more. Between the gun, scope, rangefinder, brasss, bullets etc I to have a small fortune invested and am a little dissapointed that I am having so much trouble getting the quality components that I need. Factory ammo is not only way to expensive to shoot but I have had velocity problems with the factory ammo I received as well being considerably higher in velocity than my original factory stuff. For me reloading is the only way I will be able to get out on a fairly regular basis and shoot. After applying for 24 years in Montana I finally drew a Rocky Mountain goat tag. Having problems with my rifle and loads just adds to the grief I am already feeling from being 52 and not in top physical condition. Getting in shape is something that I have control over. Getting loads to shoot that I can be confident in solely based on the components that are available is really something that I don't want to have to worry about. For now I am saving two boxes of the original factory ammo I received with my shooting system. They shoot unbelievably well, within the half minute that Gunwerks guaranteed. If you come up with any other solutions to our problem let me know. I appreciate the conversation we have had and look forward to more in the future.

 

[agentcooper]

Good luck on your goat and your physical conditioning! I drew my first Wyoming Elk tag this year after a five year wait and I'm really looking forward to it. I'm in the same boat you are in regarding handloading as an enabler to be able to shoot more often. Trigger time would be pretty rare if I had to pay for box ammo with the budget I have to work with.

I'd love to hear some other people chime in on this as well if they have experienced anything similar to what we have regarding inconsistent ammo and what solutions they have taken to remedy the issue. Glad to hear that your rifle is a shooter with the original factory ammo. Did you have them build a complete system for you? I sent them a 700 action and they basically made me a LR1000 clone on it, because I'm kinda poor like that. Haha. I'm running a Huskemaw 5-20 on it and I have no complaints with the accuracy of the gun once I got the brass issue sorted out. The gun definitely shoots better than I do, usually in the 1/3 to 1/2 M.O.A. range if I do my part. I run the Barnes LRX bullets though instead of Bergers though. I had a bad experience in Nebraska on a nice mule deer with bullet failure in Bergers. I have also had many successes with them as well but, I have personally witnessed two other Berger failures by hunting friends and I decided I would trade the sleek B.C. of Bergers for the predictability of the Barnes as they match my hunting and shot placement style a bit better. I've really tried to fall in love with the new Accubond LR's but I kept deforming the bullets while seating them in my LRM so I gave up. and I am only seating on 0.0015" neck tension. Thought that was kind of strange, they seem very soft.

 

[Rockfish Dave]

Sending the action off for the barrels this week.

I bought 200 pieces of brass from gunwerks. The hope is to be able to sort it into 3 groups throwing out the outliers by weight. So that I will have only 3 loads to develop... shooting for same velocity.

I'll try to get around to weight sorting my brass soon, and should be able to give sound numbers on how the weight is distributed on my sample size. Should be helpful since I bought the brass a couple of months ago.

That is in addition to my other wildcat projects....

 

[BRNG525]

agent cooper,
I did have them build me a complete system and it does shoot lights out with the factory ammo. My loads shoot great as well as far a groupings go just a considerable amount of variance in the velocities lately with both the newer factory ammo and the loads. I am seriously thinking about switching over to the LRX bullets as well as I have been shooting Barnes for the last ten or so years and have loved them. Have you shot them out to 1000 yards and if so what kind of groups are you getting? So far I have stopped everything in their tracks with the Berger's but I have read other things about the Berger's that lead me to believe that they could fail if you don't hit just the right spot on the animal. Obviously I wont switch before my Goat hunt but I think next season I will give the Barnes bullets a try. I have always had good luck with the Nosler bullets shooting well but have not tried the LR's yet.

 

[Swamplife]

Rockfish Dave wrote: How much free bore would you recon?
I personally would like to run 140gr - 180gr.




Hello LRM Shooters


I'm using a JGS reamer spec'ed at .318 neck and .150 freebore. I have to skim turn my necks to .016 and the COAL to the lands with a 180 hybrid is 3.555. I'm a little long in anticipation of the 195's. But if the heaviest you want to run is 180's, the least freebore I would run is .120. I had the original Gunwerks reamer and according to my measurements it had like .069 freebore which was too short IMO. The original reamer had a tighter neck and later lots of brass had thicker necks causing excessive pressure. Gunwerks redesigned their reamer to accommodate the thicker necks but I don't know if the freebore was changed or not. Rather than change to the revised Gunwerks reamer I decided to just go with a reamer that required neck turning and throated to my liking. Anybody who is going to neck turn and weight sort. Turn all your necks first then sort them, it does matter. With a load of 73grs of H1000 and 180 hybrids jumping .010 with sorted brass within 1gr and .001 runout measured on my NECO. It will shoot .9 @ 300yds. Velocity on my crony is 3050fps but if you calculate by drop it's 3125fps.



Darren

 

[trappers son]

wow you boys are having a hell of a time.... that brass problem seams pretty shameful.... I was pondering the idea of 7lrm last year but designed a wildcat off of the 7 mm weatherby mag.... the 7mm weatheby has the exact same case capacity as the 7lrm, mine has 3.5 grains more than that but the big thing is getting it throated right. If they are not running with enough throat they are getting velocity from over pressure...
7mm weatherby brass is expensive but it is good, it is always consistent, and I sort mine by .2 grains. shooting rigs are like a chain.... it won't shoot good if there is a weak link or an inconsistency in any component.... wish you the best

 

[Swamplife]

The first lots that Hornady made for Gunwerks sorted consistently. Later lots got more inconsistent in weight and neck thickness. I was able to purchase 500 cases from a member here that was from the first lot Gunwerks recieved. I sorted them to within 1 grain and the 500 pcs broke down into 5 lots.


Darren

 

[rooster721]

Good luck on your goat and your physical conditioning! I drew my first Wyoming Elk tag this year after a five year wait and I'm really looking forward to it. I'm in the same boat you are in regarding handloading as an enabler to be able to shoot more often. Trigger time would be pretty rare if I had to pay for box ammo with the budget I have to work with.

I'd love to hear some other people chime in on this as well if they have experienced anything similar to what we have regarding inconsistent ammo and what solutions they have taken to remedy the issue. Glad to hear that your rifle is a shooter with the original factory ammo. Did you have them build a complete system for you? I sent them a 700 action and they basically made me a LR1000 clone on it, because I'm kinda poor like that. Haha. I'm running a Huskemaw 5-20 on it and I have no complaints with the accuracy of the gun once I got the brass issue sorted out. The gun definitely shoots better than I do, usually in the 1/3 to 1/2 M.O.A. range if I do my part. I run the Barnes LRX bullets though instead of Bergers though. I had a bad experience in Nebraska on a nice mule deer with bullet failure in Bergers. I have also had many successes with them as well but, I have personally witnessed two other Berger failures by hunting friends and I decided I would trade the sleek B.C. of Bergers for the predictability of the Barnes as they match my hunting and shot placement style a bit better. I've really tried to fall in love with the new Accubond LR's but I kept deforming the bullets while seating them in my LRM so I gave up. and I am only seating on 0.0015" neck tension. Thought that was kind of strange, they seem very soft.

I've wondered for a long time what the 7LRM makes for velocity with the LRX bullets... nobody has ever given me a response when I've brought it up* Would you mind me asking what yours makes for speed?

 

[agentcooper]

Both weight Barnes shoot under 1/2 M.O.A. with sorted brass. I get 3025 fps with the 168's and 3295 fps with the 145's. Funny thing is, even with the difference in B.C. and velocity for both loads, they retain nearly the same velocity at 1000yds if I remember the ballistics charts correctly.

I shot a muley in region H in WY last year at 575yds with the 145's and it performed excellent. It was probably the strangest shot I've ever had in my life though. He was thrashing his horns in some junipers broadside, as the shot broke, he decided to spin around and face away from me! The bullet broke the right femur on entry and broke the left scapula on exit. Sometimes it's better to be lucky than good.

I've shot both Bergers and Barnes on game and I think they both perform well but, I don't know what a Berger would have done on that shot. I would pray the fragmentation would have made it through to pass the diaphragm. Anyone ever have a shot like that with Bergers? If so, what were the results?

 

[jrdp74]

First post!

I was having a heck of a time getting my LRM to group over the last several weeks. I found this thread and a couple others on the forum and took what I could from it and I finally started getting the group sizes I was looking for. Thanks for all the great info!

I've noticed the neck thickness between brass I bought over a year ago and recently at about .002 difference (new cases smaller) and the case weights almost 12 grams apart. Once I started sorting the brass and playing with seating depth I was on the right track. The 168 Barnes LRX have always grouped pretty good as long as I seated them about .040 off the lands, at least putting 2 in the same hole. 180 Hybrids .060 off and 180 VLDs .040 off. As soon as I get over 3100 fps I start getting plunger marks on the case. Accuracy is great now running 3000 to 3050 with the Bergers. Again thanks for all the great info!!


Hart 25.5 in 1:9 barrel
Harrel brake
Stiller Predator action
Jewell Trigger
McMillan Rem hunter Egde stock

 

[Rockfish Dave]

What was your load for the 168gr LRX?

[snip]The 168 Barnes LRX have always grouped pretty good as long as I seated them about .040 off the lands, at least putting 2 in the same hole. [snip]

 

[jrdp74]

What was your load for the 168gr LRX?

68 gr H1000 .40 off the lands Federal 215 primer and about .02 neck tension. Average about 3100 fps.