Long range labor of love comes to fruition: LRI 7mm-300WM

[ZLBubba]

When I was in the Army, I found a 7mm Rem Mag at a local pawn shop that I bought and used for deer hunting in NC. It shot pretty well for a factory gun with a whip barrel, usually 3 shots into .75" at 100 yards with hunting ammo. Certainly good enough to kill the whitetail rats that are infesting the mid-Atlantic states. However, after moving to Maryland in 2010, the rifle just sat in my safe and wasn't getting much love and I constantly thought about what to do with it. Once LRI offered it's group buy last year, I knew I had the answer.

I bought a medium palma 7mm 1:7.7 twist barrel from Bartlein and an AIAX chassis, and sent the rifle, barrel, and stock to LRI for them to work their magic. I really wanted to venture into the world of wildcatting and figured this was a good time to try it out. I ordered the rifle to be chambered in 7mm-300WM (or 7mm Practical).

Here she is:

The rifle came out beautifully, with one catch: the reamer used made the neck so tight that I had to have the Norma brass I'd ordered neckturned. Since I lacked the equipment or patience to neck turn, I spoke with Josh Lapin at Copper Creek Ammo to build out a good load out of neck turned and necked down Norma 300WM brass, 180gr pointed Hybrids, and the powder of his choice. However, we had a hell of a time finding a good load with H1000 as this rifle was pretty finicky.

I had about 80 of the cases Josh had worked on in my stash so I started over with a tub of Retumbo trying to find a sweet spot for this beast. I loaded up a pretty good ladder test for these test rounds, but with how much work I've had this summer, I haven't been able to shoot them since I loaded them in June. Well, I finally found a free day to head out to my local range and put my new loads through the paces with the rifle. If I couldn't find a good load, I was ready to re-barrel this project to a 300WM, thereby cutting my losses and the headaches of wildcatting. I was ready to raise the white flag.

Much to my extreme pleasure, I found two solid accuracy nodes with Retumbo and the 180gr pointed hybrids. The load that I finally settled on is easy on my barrel (comparatively speaking for this cartridge), shows no pressure signs, and it's wicked accurate. Below is my best group of the day:

Obviously, I couldn't be happier with this load's potential. It's damn hard to complain about a rifle that shoots in the .1s.

Josh's got the rest of my brass and will be loading up the following recipe: 180gr pointed hybrids over 73.5gr of Retumbo, neckturned and necked-down Norma 300WM brass, FGMM magnum rifle primers, loaded @ 3.592" OAL. Needless to say, my hats off to Josh at Copper Creek and the folks at LRI for helping me turn this project from a headache to a heart throb. I need to chrono this load but I imagine I'm somewhere between 3050 and 3100 fps. I can't wait to see how this round works at over 1k.

 

[dworrel]

Been thinking about one of these myself. I have so much 300WM brass lying around.

Cool build. I have a couple 7WSM's, 7LRM.

7 LRM has been the easiest to get to shoot so far.

 

[ZLBubba]

I started with a great 7WSM but using a short action, I never got the velocities that I really wanted. I'd wished I'd gotten an LA so that I could seat the 180s out long. That was when I started researching the various 7mm wildcats, and decided to go with the 7mm Practical.

Admittedly this cartridge requires some work necking down the 300WM case, and then with the added neckturning, it wasn't something I could do on my own. I plan on learning to neck turn on my next batch of ammo, but for now I'm just glad the project finally came together.

 

[Wannashootit]

One of my sons has been putting the bug in my ear for a .338 LM for additional plinking fun at the 1K yard range. Been trying to convince him that the .300 WM is a better choice at that range for a variety of reasons, but there's still the "cool" factor of the .338.

I had been thinking about "what if you necked down the .300 WM to 7mm..." and came across this thread. I'm a big fan of the 7mm bullets (my LR rifle is a 7-08) and the thought of pushing the 162 Amax well over 3000 fps is intriguing.

Barrel life....gotta be worse than the .300 (smaller bore), but how much so...is this only a 1000 round barrel?

Ballistics... can this outperform the .300 at at 1K yards with the higher BC 7mm bullets?

 

[ZLBubba]

I'm not sure what the barrel life will be on this gun, but the load I'm using isn't pushing the pressure limit. I think it will be comparable to a 300WM.

In terms of whether it will ballistically outperform a 300WM, that's a solid "maybe." On paper I think a 300WM with a 230 hybrids at max pressure would outperform a 7mm-300WM with 180 hybrids at max pressure. However, as we all know, very few guns shoot best at max pressure, so depending on where the honey load is for each rifle would probably determine which rifle won out over the other. And honestly, the difference of 100 fps or 200 ft/lbs of energy doesn't mean a big deal to me, provided the accuracy is there.

Now, for a 1000 yard use case, all of these rounds will be more than enough to hit easily at 1k and ring that steel pretty damn loud. I can hear my 6Creed just fine at 1000, and all of the rounds you're talking about have quite a bit more umph at 1k than it does. I'd honestly say anything over 300WM at 1k is overkill when quite a few guys on this board are shoot 6mms at that range and ringing the steel consistently. I have two 300WMs so I love that round, but this 7mm is really fun and easy to shoot.

 

[Engine 22]

I have a 7mm-300WM in the works myself. This thread gives me confidence that I have made a good choice by going with the 7-300 over the other big 7s. It also helped that I have a ton of 300WM brass and great dies .

 

[SporterII]

Good results, potential is there. Wish my la. had a Mag bolt face. I have a 280 and would like to be where you are right now. Thanks for posting.

 

[scpaul]

Congrats. on the 7/300, I'm in the process of building a 7mm Valkyrie myself. It's basically a 7/300 with an Ackley treatment.How long is the barrel on your rifle? In the past , with magnums and overbore ctgs. I found that the slower powders generally gave more consistant accuracy and velocity. Retumbo is one of my favorites, you might also try IMR 7828, 50 BMG, RL-25 and other powders at the bottom of the speed list. I'm looking for some RL-33 now. I can't prove it yet, but the slower powders seem to be easier on barrels. I also have a 300 Ultra mag. that I bought used and have put close to 1k rounds through it myself and it's still sub-MOA, I don't have any idea how many rounds were through it when I bought it. I'm using a rechambered 7mm Rem. Mag. bbl. just to see how I like it to begin with but plan a 30" bbl. when I replace the one I've got on it now. Any other good loads you come up with I'd be interested in trying and when I finish mine I'll return the favor. If this suits you pm me. Thanks, good luck and congrats, Paul

 

[Hunt4life]

I am getting the same from a 7rem mag, 73 gr retumbo, 180 berger, 3100 gps and 5.8-6 mils to 1000. No signs of pressure at all, though I worked up from 68.

 

[ZLBubba]

Thanks for the kind words.

The barrel on my rifle is a standard 26" Bartlein medium palma, and fluted. I've been really happy with Retumbo thus far so I don't see myself switching unless I can't find it anymore. As they say, "If it ain't broke, don't fix it!" Or maybe I just don't want the hassle of doing anymore load development...

Yeah, I'm more than happy with 73.5gr Retumbo load. I'm not positive what the muzzle velocity is until I chrono it, but I do imagine I'm somewhere in the 3100fps ballpark. With the pointed hybrids, I usually get about 5-10% improved BC, and noticeably better consistency from round to round. I tell you, I have yet to find a rifle that doesn't shoot those Berger hybrids well.

 

[Wannashootit]

On the subject of neck-turning you mentioned...
Forgive the ignorance on the subject...
I know it may be needed for an overly tight chamber, but is it also caused by the brass thickening from necking it down?

Can the necks be thinned by turning on a lathe?

 

[ZLBubba]

On the subject of neck-turning you mentioned...
Forgive the ignorance on the subject...
I know it may be needed for an overly tight chamber, but is it also caused by the brass thickening from necking it down?

Can the necks be thinned by turning on a lathe?

That's a good question that I defer to people more experienced than myself. The neck on my 7mm-300WM is particularly tight, but you can certainly use a reamer that doesn't require neckturning. In fact, I wish that's the one that had been used on my rifle. Nonetheless, neckturning done right does improve neck conformity from loaded round to the next, but I've never done it myself. I'm having Copper Creek prep the brass and load the original 400 rounds and then reloading those once I've shot through them. Once I burn this barrel out, I'll be deciding whether to take on neckturning to stick to rounds that don't require it. Right now I'm leaning toward neckturning since this rifle turned out so damn well, and I'm positive it's in part because of the excellent brass prep by Josh at Copper Creek.

Whether necks can be turned on a lathe, I have no idea. I imagine it can be done, but I don't imagine it would be the preferred method.

 

[KYpatriot]

A long throat 7 rm will get 3000-3050 with retumbo and 180 hybrids if you don't want to wildcat. Seems like you should be able to get 3150.

 

[jonthomps]

Congrats on a great rifle! I seriously looked into a 7/300WM before deciding to stay with a 30 cal and go with a 300NM. It's good to see yours shooting so well. 6 mils or a tick less of elevation at 1k is awesome.

 

[308220]

Sweet looking gun. And damn good shooting. Building a 7mm myself. But in a 7mm rem mag. Little more barrel life.

 

[ZLBubba]

I'll definitely agree that a 7mmRM is a great cartridge and often overlooked. I'm as curious as everyone else when it comes to barrel life, but the good news is that I've kept exact track of how many rounds this rifle's seen, so I'll be able to give a good accounting next year when I expect to be through this barrel. I'm honestly thinking I'll get 2000 rounds of 1/2moa barrel life, but we'll see. I know that I could probably squeeze another 100 fps out of this rifle, but between less barrel life and the accuracy node that I'm at, it's just not worth it to me. I'll take a .1" shooter at 3100 fps over a .4" shooter at 3200 fps any day.

If Ballistic AE is to be trusted, then this load at 3100fps at the altitude I'm shooting, and with the added BC from pointing the bullets, should shoot right around 5.1mils at 1k. That's half what my 308s shoot at 1000, but I haven't field tested this dope so I'll have to let you know once I get a chance to go shoot again with Ed Shell. Needless to say, I can't wait to hit the range out at Central Virginia Tactical.

 

[redd0311]

Tag

 

[Bob L Swagger]

Justin,

Congrats on such a fine stick! I played with the idea of this caliber in the past & it still may be in the cards after you put it through the wringer. I look forward to future accumulated data.. Keep us posted!

Best regards,

Bob

 

[Frank Green]

When I was in the Army, I found a 7mm Rem Mag at a local pawn shop that I bought and used for deer hunting in NC. It shot pretty well for a factory gun with a whip barrel, usually 3 shots into .75" at 100 yards with hunting ammo. Certainly good enough to kill the whitetail rats that are infesting the mid-Atlantic states. However, after moving to Maryland in 2010, the rifle just sat in my safe and wasn't getting much love and I constantly thought about what to do with it. Once LRI offered it's group buy last year, I knew I had the answer.

I bought a medium palma 7mm 1:7.7 twist barrel from Bartlein and an AIAX chassis, and sent the rifle, barrel, and stock to LRI for them to work their magic. I really wanted to venture into the world of wildcatting and figured this was a good time to try it out. I ordered the rifle to be chambered in 7mm-300WM (or 7mm Practical).

Here she is:

The rifle came out beautifully, with one catch: the reamer used made the neck so tight that I had to have the Norma brass I'd ordered neckturned. Since I lacked the equipment or patience to neck turn, I spoke with Josh Lapin at Copper Creek Ammo to build out a good load out of neck turned and necked down Norma 300WM brass, 180gr pointed Hybrids, and the powder of his choice. However, we had a hell of a time finding a good load with H1000 as this rifle was pretty finicky.

I had about 80 of the cases Josh had worked on in my stash so I started over with a tub of Retumbo trying to find a sweet spot for this beast. I loaded up a pretty good ladder test for these test rounds, but with how much work I've had this summer, I haven't been able to shoot them since I loaded them in June. Well, I finally found a free day to head out to my local range and put my new loads through the paces with the rifle. If I couldn't find a good load, I was ready to re-barrel this project to a 300WM, thereby cutting my losses and the headaches of wildcatting. I was ready to raise the white flag.

Much to my extreme pleasure, I found two solid accuracy nodes with Retumbo and the 180gr pointed hybrids. The load that I finally settled on is easy on my barrel (comparatively speaking for this cartridge), shows no pressure signs, and it's wicked accurate. Below is my best group of the day:

Obviously, I couldn't be happier with this load's potential. It's damn hard to complain about a rifle that shoots in the .1s.

Josh's got the rest of my brass and will be loading up the following recipe: 180gr pointed hybrids over 73.5gr of Retumbo, neckturned and necked-down Norma 300WM brass, FGMM magnum rifle primers, loaded @ 3.592" OAL. Needless to say, my hats off to Josh at Copper Creek and the folks at LRI for helping me turn this project from a headache to a heart throb. I need to chrono this load but I imagine I'm somewhere between 3050 and 3100 fps. I can't wait to see how this round works at over 1k.

Awesome!!!!

Later, Frank
Bartlein Barrels

 

[ZLBubba]

Frank, y'all turn out some great barrels. Bartleins are my first choice whenever I do a new build.

Bob, I appreciate the kind words. I'm keeping close track of how many rounds I get out of this barrel and how the round performs for life of the project. I'm going to schedule some LR time with Ed Shell and see how this performs beyond 1k.

 

[916Plinker]

Congrats, very nice build!