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Discussion Starter · #1 ·
Well I just myself a Rockchucker reloading set as well as a .308 Neck and FL die as well as a 7mmRM FL die. I need some help with some help with a few start loads for the following (which I will get dies for by the way).

.308
155gr Lapua Scenar
168gr SMK
165gr Nosler Accubond

.7mm
168gr Berger VLD (Match and Hunting)
160gr Nosler Accubond

.375 H&H Magnum
This is a toss up here, I would like a high BC 250gr bullet for long range target shooting and some longer range hunts. My Speer reloading manual says I can push a 250gr projectile at 2944 fps with a maximum load, I assume a medium-hot load will net me around 2850. Then I'm thinking a good 'ol 300gr Failsafe for big game, I don't like the Partitions because the nose gets flattened in my mag well.

Now one thing I know is that a shorter barrel = less velocity... Can I use a slightly faster powder than whatever is currently used in a full lenght barrel to make up ome velocity in a shorter barrel? I want to cut my 7mmRM down to about 18", throw on a folder and a suppessor so that it fits better into tiny places, that and so the missus can shoot it better.

If my bullet selection is off please let me know. The .308 will almost exclusively be a range gun with hunting bullets thrown in as a back up incase I need to use it in a hunting situation. The 7mmRM will be used in both situations about equally, I know the accubond is proven and the VLD is more suited to long range shots. The .375H&H is kinda going to be my go to gun for all hunts, fast 250gr bullets for medium game and maybe moose and the 300gr slugs for bear. I want a 250gr bullet that can reach out and touch something if needed. And yes I will put the time in at the range that is needed to become certain the bullet will go where it needs to go everytime I take a shot at a given distance. For further insurance on long shots I have a Kestrel wind meter, a Laser range finder, Mil measurement system on both my scope and my spotting scope so I can be sure of the distance.

Thanks fo any and all help you have to offer.
 

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I can't give you any advice about the .308, but I have been using the 160 gr Accubonds in my custom heavy barrel 7MM RM. I currently use 59.0 gr of IMR 4831 and WLRM primers which is not very hot, but it shoots ok out of my gun. I have not experimented with it since I loaded those up but if I remember right, it's shooting under 3/4 to 1/2 MOA without me going back and checking. The velocity is only a little over 2850 fps out of a 26" barrel. I was always going to try the Berger VLD's but when I was shooting the 7mm I couldn't get my hands on any of them. RL-22, or IMR 4350 also shoot good out of my rifle.

As for cutting off your barrel.... I can't remember how many fps in general you gain per inch but I thought it was somewhere around 100-150 fps or so, and I don't know how fast you can push that .284 bullet out of a short barrel like that ether. I would think that it would not be too much below what the published numbers are.

The bottom shot was to get on target, the top hole I'm claiming as a "Flier". This is my 7mm Rem load with the 160 Noslers.

I'm sure someone else will chime in with some further information. Hope you didn't forget the seater dies!

 

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Sounds like you may be planning to do some shooting?

To answer your middle question first, because peak pressure occurs about one to two inches into a bullet's travel down the bore, unless you have a barrel shorter than that, you can't get increased velocity from faster powders for a given peak chamber pressure. For normal barrel lengths, the powder that is fastest in a long barrel will also be fastest in a short barrel. Fast powders produce lower pressures after the peak because they burn out sooner. That drops the pressure that follows the peak as compared to a slower powder. This can improve accuracy by presenting less muzzle blast to the base of a bullet, so the highest velocity load you can find is often not the most accurate. You normally lose 20-40 fps per inch of barrel in most guns, but the exact number is individual to the powder charge and bullet used, and also to the barrel lengths you make the comparison with.

For the .308 accuracy work, I've had excellent results from Varget, IMR4895, IMR4064, Reloader 15, Vihtavuori N140, Winchester 748, and Accurate 2520 (deburr case flash holes for this powder and for 748) at different times and ranges. Ramshot TAC and the new Reloader 17 look promising on paper, but I haven't wrung either out yet. Varget is probably what I would pick to start with. It will span your whole bullet weight range. It is bulky enough that it won't quite give you the velocity IMR4895 or 748 can, but it has good temperature immunity and is less picky about primers in the .308, and that cuts down on some of the variables while you get started.

What cases will you use? .308 case brands vary in capacity by about 3 grains, so the brand is critical to load data. All the data on the Hodgdon site uses Winchester cases, as do the OCW loads listed on Dan Newberry's web site. They have the most capacity. I like Newberry's round robin method of load evaluation, BTW. I think you'll find reading his whole site useful. It would be a good place for you to start looking at loads.

Be aware the old 168 grain SMK, originally designed for 300m International Rifle shooting in the late 1950's, is only good to 600 yards. From a .308 tac rifle I've watched it go unstable and tumble before getting to a 750 yard popper target. At the Long Range Firing School at Camp Perry, nobody using it could stay on paper at 800 yards. Same problem. At .308 velocities, somewhere around 650 to 700 yard it gets into the transonic range and becomes unstable. The newer 175 grain Sierra MatchKing, designed in cooperation with the military for sniper ammo, does not get unstable in the transonic velocity range and has made hits to 1200 yards and beyond in the sandbox. I've switched over to it for long range, and no longer buy the 168's (though I'm still using up my last 1000 or so from very large old bulk purchase).

I haven't tried the 155 grain Scenar or the new version 155 Grain Sierra which matches the Lapua's BC's. That's another one you might look for.

I'll leave your other chamberings to those who own them to address.
 

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Discussion Starter · #4 ·
I was planning on using the FGMM brass for the first 4-5 firings for the .308 then ordering some Lapua brass. For the .375 I was once again going to use the Federal Gold Premium brass for a few firings then order some Nosler custom brass. Same for the 7mmRM.
 

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Federal has a reputation for being soft. If you've had time to read his site, you'll have noticed Dan Newberry doesn't consider it suitable for reloading at all because of that. The Lapua cases, at the other extreme, are the best you can get and will last a very long time if you keep the necks annealed.

That said, if the primer pockets on your GMM brass were not shot lose by their original loads and you aren't going for a maximum load, you should be able to get some more work out of them. If you find the primer pockets getting loose, though, pitch them.

I can tell you the old Federal GMM .308 load for the 168 grain SMK was 43.5 grains of IMR4064 over the Federal 210M primer. This runs about 52,700 psi and is slightly compressed. I understand they now use Reloader 15, as Lake City does for M118LR with the 175 grain SMK, but I haven't pulled any to study the load as I did with the older stuff? Based on tearing down and duplicating the old Federal load, it appears to me they used a burn rate adjusted canister grade powder, like reloaders buy, rather than the usual unblended bulk powder manufacturers normally use. It makes sense from the standpoint of consistency for match grade ammo, but still, that is an inference and not a proven fact, so if you are going to try it, work up from 10% lower, watching for pressure signs, just to be safe.
 

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For only twice the cost of cutting and recrowning the barrel on your 7RM, you could probably buy a 7-08...which is about the velocity you'll get from an 18" long 7RM barrel. I mention this because I had a buddy in CA who was peacock proud of his 7RM carbine and became more than a little testy when I told him it wouldn't shoot his 140gr loads any faster than my .270 Win. He argued vociferously, but the chronograph doesn't lie. In fact, he was almost 150fps SLOWER than my handloads. :) He grumbled about that gun for a few years before selling it off to some other schmuck who didn't get the concept.

Besides being seriously over-bore, the only saving grace for the 7RM is when it is shot from a long barrel...even a 24" tube will hamstring this cartridge, somewhat. The ONLY thing cutting it to 18" will do is give it substantially more muzzle blast than a 7-08 or, heck, even a 7x57. Spare your wife the misery.
 

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I will share my best target load in 308. I am a relative newbie to reloading but have had amazing results with max load of 44 grains of Varget and the Hornady 168grain A-Max It has shot wonderful in 3 different rifles. Two of them would shoot better than I could hold them.. The A-Max are pretty cheap in boxes of 100 and work well for yotes and pests. They also have a pretty good BC I think it is around .4 something. BL(c)-2 worked well also and metered better.
 

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That's interesting info on the 7RM cut down to carbine length. One of the rifles I hope to add to the collection is an H&R 301. They offer this 18" barrelled mannlicher in 7RM and 300 Win Mag. I always wondered how much velocity would be lost or how I would load for it. I can imagine how much noise it would make though. Yikes.
That's for the guys who are already deaf, and want their deer cooked by the muzzle blast!! :eek:
 

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Discussion Starter · #9 ·
I would plan on shooting the 7mmRM with a suppressor attached and I kinda wanted to keep the magnum bolt face. If it was a short action then I'd put one of the 6.5 chamberings in it or the 7mm-08.

I currently have Accurate 2460 powder and some CCI primers with a box of 168 SMKs. Should I ditch my federal brass and just go get some Winchester brass from sportsman warehouse or go with Remington brass?
 

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Federal brass has never lasted as long as Winchester for me. Although keep in mind a new batch of Win .220 swift brass I bought needed the flash holes de-burred quite a bit on every case. Looked like I struck gold after cleaning them out! Every case had a big burr on one side due to the fact that Winchester punches out their flash holes. Although de-burring can be expected on most brass unless you are using Lapua, Norma, or Nosler. They drill theirs out.
 

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You can still work up in the Federal if its primer pocket is still tight. Figure that a load good in the Federal will probably need a bout half a grain more powder to match the pressure and velocity in a Winchester case. They have larger capacity in .308.
 

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Discussion Starter · #13 ·
Well I did some .308 brass sizing today and i have something that might or might not be an issue. Starting at the widest part of the shoulder I have a scratch thats 1/8" wide and 1/4" long running lengthwise down the case. This scratch is in the same exact place on all 20 rounds I FL resized. Is it an issue or just leave it alone?
 

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Do you see that scratch on any of the brass that has not already been sized? In other words, is the scratch coming from your reloading die or the barrel of your gun?

My 270 chamber always leaves a very small, crescent-shaped impression on the neck of a fired case. If I was having any accuracy problems, I could use it to index how I am inserting rounds into the chamber. :) In your case, it sounds like your sizing die may have some debris or damage, internally.
 

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Discussion Starter · #15 ·
They're unscratched beforehand, the scratch is defineately coming from the sizing die. What would be the best way to flush that out? Some brake cleaner?
 

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Well I did some .308 brass sizing today and i have something that might or might not be an issue. Starting at the widest part of the shoulder I have a scratch thats 1/8" wide and 1/4" long running lengthwise down the case. This scratch is in the same exact place on all 20 rounds I FL resized. Is it an issue or just leave it alone?
I'm assuming the scratch is on the body of the case. You can run some break cleaner or carb cleaner through your die. Take out the decapping pin/expander ball unit first. You should be able to see any obvious obstructions. I would also run a cloth in there to try and wipe out anything that may be a little stubborn, then clean it again with the spray. Make sure you put some type of oil or protection on the die after you are done to prevent rusting. It is always a good idea to clean out new dies due to the fact that there might be some junk in there.

What type of case lubricant are you using, and how deep is the scratch?
 

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Discussion Starter · #17 ·
The scratch is fairly shallow and I'm using RCBS Case Lube 2. I'll take it apart and clean it out, I failed to do to that before I started resizin, thanks.
 
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