Bad news on long-awaited 7RUM Shaw barrel.

[bigngreen]

Savages answer was to open up the action and put more diameter into the barrel, they didn't do that for nothing. It's seriously a 150-200 dollar solution and it's done while trueing the action so you gain a trued action and a shank size you can screw anything you want into it from any prefit barrel maker!!
Any of my personal Savages go large shank, not because I think I need more strength but because I gain flexibility to burn up a cheap barrel then screw on another one like the 7RUM barrel I have here that cost me 40 dollars with no wear at all. I think the small shank is strong enough personally from what I've seen from the RUM's I've built on them and from what a lot of other guys do!!

The Savage 338 Lapua is built on a large shank, I've read that the 338 Lapua can swell the chamber on a small shank Savage so that seems to be more evidence that more shank is the answer for larger cases and more pressure!!!

Anyway good luck, I really want to see you get this built so we can all see how long the barrel last

 

[mrultramag]

Maybe I got lucky. I have a 7 rum mod 700 LSS 26" that I have over 700 rds thru. It still shoots as good as it did when it was new. It shoots several loads under 1/2 moa at 200 yd. I used to load it pretty warm the first 500 to 600 rds. Now I just run it at STW speed with 140 AB and IMR7828 at 3425. I've taken it to 3570 with 140 AB and retumbo, then ran out of nerve even though all was still well except the accuracy was not there. I had a good lot of RL 25 that shot the 150 partition at almost 3500 accurately as in 1/4moa at 100, and was happy. The next lot wouldn't come close. I've always only shot 3 shot groups, let the barrel cool and clean every 20 rds or so. 160 AB and retumbo at 3250 is a good load too. its possible that the barrel could go south any time but I haven't spent my time measuring the throat and fretting about it. its a hot rod and hot rods eat parts. I'll shoot it until it don't shoot well and then rebarrel to 7 rum again. I don't own a STW but these guys are probably right when they say the 7 rum is a small step up for burning 10-20 grains more powder. A longer barrel will pay dividends however. If your gonna run hot loads just be careful. work up your loads and pay attention to things. On my Rum's primer pocket expansion is one sure fire sign your too hot. Good luck with what ever direction you go. I don't think you'll go wrong with an STW either. Or a 300 rum. Not any flies on the 270 wby either. especially if your wanting to go light and fast, 3500 with a 130 out of 26" bbl is no big trick with 7828.

 

[Max Heat]

I'm looking for WAY more "trick" than 130's (or even 140's) @ 3500. That's "chump change", in my book. The standard remington 7mag can pull THAT off, using RL19. But since that IS what I already have, I need significantly more than that to step up TO, in order to make it worthwhile. I've heard that getting 180's to fly at 3500 is a piece of cake for 7RUM. But that's the high end of the 7's weight range. I'm looking at working near the lower end of that range, but with maximum "heat" numbers on what the muzzle spits out. I'm taking about 120's flying at nearly 4 grand, using 96-97gr of RL25. My goal is to work up to that. All I need, is something to work WITH. But those dang stories I keep hearing about over-sized or swelled RUM chambers do have a tempering effect on my thoughts of going small shank RUM, via re-chambering my existing 7RM barrel. But for a burn-it-up-in-no-time barrel, it does appear to be the most eligible candidate. Then I can take my time on finding the long-and-fat barreled big-shank 7RUM setup that I am truly seeking. Roughly how much DOES it cost to have a barrel machined out to a larger/longer chamber?

 

[Lefty7mmstw]

I'm looking for WAY more "trick" than 130's (or even 140's) @ 3500. That's "chump change", in my book. The standard remington 7mag can pull THAT off, using RL19. But since that IS what I already have, I need significantly more than that to step up TO, in order to make it worthwhile. I've heard that getting 180's to fly at 3500 is a piece of cake for 7RUM. But that's the high end of the 7's weight range. I'm looking at working near the lower end of that range, but with maximum "heat" numbers on what the muzzle spits out. I'm taking about 120's flying at nearly 4 grand, using 96-97gr of RL25. My goal is to work up to that. All I need, is something to work WITH. But those dang stories I keep hearing about over-sized or swelled RUM chambers do have a tempering effect on my thoughts of going small shank RUM, via re-chambering my existing 7RM barrel. But for a burn-it-up-in-no-time barrel, it does appear to be the most eligible candidate. Then I can take my time on finding the long-and-fat barreled big-shank 7RUM setup that I am truly seeking. Roughly how much DOES it cost to have a barrel machined out to a larger/longer chamber?

In a standard barreled stw or rum you had better have an iron deficiency of you want to go over 3500 fps on a 140 (by any significant margin) or 3400 fps on a 150 because eventually you will eat a bolt. I have pushed the 120 sierra to 4K fps even with the 7 rum(the stw tops out around 3700 fps with a 120) by using an extremely heavy dose of AA 8700. It was almost 1 grain powder for 1 grain bullet. If you go longer than 26" your barrels will do somewhat better, but I wouldn't bet on more than 25 fps per inch. The stw is down to around 12K psi at the end of a 26" barrel, so you aren't pushing very hard anymore.

 

[Lefty7mmstw]

Roughly how much DOES it cost to have a barrel machined out to a larger/longer chamber?

You are looking at around $200 if you are in my neck of the woods for a simple re-chamber. Could be a bit more or less depending on the amount of work necessary. I got that quote looking at re- chambering a rem 700 in 7mag I have. I decided to shoot it out and re-barrel to a better caliber(7stw).

 

[mrultramag]

max heat- you heard 180's at 3500 were a piece of cake for the 7 rum... you heard wrong. Even with a 30" bbl, I think you'll do good to get 3600-3650 with a 140.

 

[Max Heat]

It looks like you are on the ball there. I DID hear, or actually say, wrong. What I heard 3500 piece of cake about was the A-max 162, NOT the 180. Sorry about that one. That's more than I on figured on for re-chamber to RUM. The factory sporter barrel hardly seems worth putting 2 bills into. As far as pushing 120s out at 4k, there's someone else who says they've done it with the RUM. That's ALL I'm looking for, nothing more. That is at least until they finally start producing/selling the sabot that would allow to shoot the high-BC 6mm hundred grainers out of 7RUM. That should push velocity somewhere upwards of 4300fps. I have fantasies about jumping into 6mmBR, enjoying a big advantage. But I don't know if that would even be legal. My "final" goal is to achieve that magic 1:1 ratio of powder to bullet! But since they are still working on the sabs (they have been for some time now), I'll cross THAT bridge once it actually gets built. I'm looking at lefty's post a little bit more, and I'm going to have to voice my opinion on something. 120@3700 being tops for the STW really does blow, compared to 4K on the RUM. That extra capacity really DOES seem to make quite a difference, when it comes to the lighter weight rounds.

 

[Lefty7mmstw]

I never really pushed the 120's with more than a couple of powders with the stw, but was at full case with I 7828 and close to 3700 fps, so I didn't putz around. I probably could have gotten more, but I went with the 140 as a better round for deer. The 7ultra with 120's and aa8700 wasn't terribly accurate, but it was the one with the bad chamber and was never really accurate. I put around 100 rounds on the rifle trying to get it to shoot and breaking reloading dies, etc. before I gave up and got my money back. It doesn't feel any different shoving a case in that breaks the die from a normal one. The subsequent ones are easier though.....

 

[Max Heat]

Maybe I was too quick to bad mouth the STW on the velocity that was quoted. I'm sure it could do better than that using say, RL-22 (or maybe even 25, which seems to be what the RUM likes, from what I understand), because I do know that 19 burns too fast & pressure gets too high, on loads exceeding approximately 70-72gr. But I don't think it can beat, for loads below that threshold. I hope I didn't just open my self up for a big backlash on that one! Let me just say that I've actually seen 3700 (3680@15-20ft downrange, running the NBT120's) out of the standard rem mag already, using 75gr of 19. But I got some varying levels of tight bolt, and swelled primer pockets, on the 10 of those that I loaded and shot. And that was in cold weather, mind you. (disclaimer) That is obviously TOO HOT for 19 - so DON'T try it, unless you don't mind running the risk of eating some bolt! Anyways, it was at that point that I knew I had reached (for all intents and purposes, actually did exceed) the 7mag's limit. There is simply NO case capacity left for trying something slower like 22, which would require more grainage to achieve an equivalent velocity, but can get the job done, while producing less of a pressure spike. That was back in like february, and I haven't fired the rifle at all, since then. But at this point, I'm starting to get real itchy for SOMETHING to happen. Being that a re-chamber-to-RUM job on the stock barrel could cost me 2 bills, I'm going to switch up on my decision (tey again), and now this is looking like the path that I should take: First off, I'll leave the savage 7RM barrel/action/rifle alone, but have the HS checked, and re-set, right down to GO+0. Then have a long (I'll take the +100fps that 30-31" will gain me, over 26), heavy contour (stainless would be nice, but not a strict requirement), large shank 7RUM barrel made (or located, if they already exist) and installed onto a new (or even used, as long as it has a minimum amount of wear) largely shanked savage long action, so that it will fit into the ultimate varmint(er) stock that I have & want to use. Since the deal would include a receiver with a big-shank SLA, it would basically amount to buying a whole new rifle, less the stock. I'd have a magazine that I could use then, too. So NOW, the question is: Where/how do I come up with the best possible deal, in going with THAT course of action?