Personally I would not build a 505 Gibbs weighing less than 12 lbs. I ususally use a profile that tapers from 1.250( about 4.5 inches from the breechface) to .950 at the muzzel . My 505 has a 23 inch barrel as I remember. NECG sells lots of nice rear sights as well as ramped front sights. They also have a special order barrel band rear sight base that includes a recoil lug. You will absolutely need a barrel mounted recoil lug on a 505 Gibbs as well as at least 2 crossbolts. You do realize that you will need a action big enough for this cartridge. It has been done on M1917 enfields but it's an enormous amount of work. Most 505's that feed reliably ( most don't because they were built by people who don't have a clue)IMHO are built on custom actions ususally costing $2500 or more assuming you want more than two shots in the magazine. Ah- Now for the stock, it had better be a good one. If that action has any movement in the stock it will wreck it in just a few shots. Laminates and fiberglass seem attractive right up till you replace them. There are lots of people on this board who have learned that lesson the hard way. IMHO the only thing that stands up to more than casual shooting of a full tilt 505 Gibbs is a REALLY well inletted piece of walnut properly crossbolted and steelbedded.Do yourself a favor and use a leather covered F990 pad and a BIG MUZZEL BRAKE. Yes the 505 Gibbs can provide some entertainment in the recoil department. Build it improperly and you will quickly place it on ebay. Build it right and you will have no problems. That takes time and money. There are no shortcuts and don't waste your time trying to find them! Expect to spend $3000-5000 for a decent reliable Gibbs-Rob

I just ran the calculations via quickload and for 100% load density,a 525 gr woodleigh and RL-22, it takes about 137 grs of powder and the velocity will be about 2343 for a 23 inch barreled 505 Gibbs. Using Rl-25 it will take about 135 grs for 100% load density, but velocity will only be about 2215fps. Pressures will be quite moderate with both powders. Neither of these powders will be terribly efficient with no more than about a 90% burn. -Rob

Hey Rob, nice hearing from you.

When do we see the first cloned Mammoth? Once you have a weaned specimen, the ideal location to "Feedlot" is here on Washington's Olympic Peninsula: Lots of forage, and a mild cool climate not too distant from Ice Age Summers. As this is a economic depressed area due to the reduction in old growth timber logging, we need the tourist attraction to bring in the $$$.

Anyway, I have fooled around a lot with Quickload and the Oehler M43. My observation: The more one approaches a straight wall case, like a 458 Win or Lott, etc., the less accurate Quickload is in prediciting actual pressures & velocities. However, I have found this error to be on the safe side, i.e., the actual pressures and velocities are lower than predicted by Quickload. I have formulated some correction factors for a few cartridges, but I don't dare publish this stuff as it is real easy to get in bad trouble (meaning ruptured cases and blow up rifles!).

For a real hoot when shooting the big bores with full or compressed loads of slow burning powder, do some shooting in the winter when you have a snow cover on the ground in front of the shooting bench. Undisturbed snow, no footprints! Fire off a few rounds, then look for all the unburned powder on the snow!!! Sorry about you gents in Tucson, this procedure will not work.

Thanks for the input, I just got in some Woodleigh 600 grain protected point for grins and giggles you might say. The action won't be done for 9-12 months depending on when the company get's enough for a production run. I almost went with the 416 Rigby and still have that option, but thought it might be interesting to play with the 505. The action is LEFT handed so why be normal...right? I do believe I'll go with the lighter bullets, I doubt a buff would know that much difference. I'm planning on a 24" barrel for weight as much as anything, although the 22" barrel may be more traditional. I know from past experience not to go with too light of a rifle, it takes all the fun out of shooting. I'm guessing that the 500 class is a good firm push instead of the super magnum slap that I've grown accustomed to with the 338 UM etc. Is the 505 capable of reasonable accuracey(that is a broad statement I know) and the ability to get back on target for another shot quickley? It is a very select few of you that have experience with the big bores, even fewer still that have hunted with them. I know African game is tuff, but I'm here to tell all of you, the deer in the UP of Michigan are some of the toughest animals I've seen. We're thinking maybe the 505 might handle them, but not sure? (One of the 95 lb does I took last year took a 250 grainer at 15 yards from a 35 Whelen and didn't even drop when hit in the shoulder she ran for 75 yards) I'm telling you guys, it was creepy, and all of us in deer camp are thinking we need something with more stopping power...lol. Thanks for the info thus far, I wasn't aware of some of the software available.

I have been reloading for about 10 years but have only followed printed manuals advice. How do you go about calculating a load for a powder you are not familiar with? To the point, I am awaiting an action for a 505 Gibbs. Alliant has a load for Reloader 22, but I was wondering how an extremely slow burning powder like Reloader 25 would react in a large capacity cartridge. I haven't tested the theory that the RL 25 is more bulky(so it would fill up the case more) or not. I have loaded RL 25 and RL-19 in the 416 Rigby for a swift A-frame and a Barnes solid and they performed very well. I use the RL25 in my 338 Rem UM and love it. I would like to economize somewhat on the number of powders I have all the time. Alliant powders are readily available and are reasonable in my area. Some thoughts from the experienced on this would be great? Thanks in advance for your help!

Get somebody with a copy of quickload to run the numbers for you if you want to try powders not in the manuals. I have a 505 Gibbs and have used IMR4831 and Rl-15 successfully. Off Hand, I believe Rl-25 will be too slow to provide anything but the equivalent of a reduced load.-Rob

What barrel diameter would you all recommend? I talked to Krieger and they said a .85 barrel at 25" would weigh in around 4.1 lbs. That seems a wheeee bit light, but I'm really new at this. Since some of you guys have or have built this rifle what is the min/max weight you would recommend? I was looking at one of the Accurate Inovations stocks, any thoughts on this? Also, looking for suggestions on where to get sights, other than Brownells(I've looked there already). Thanks for sharing your knowledge on this, hopefully it will help me avoid some of the pitfalls. Thanks also for the warning on the recoil. I am taking that to heart, my friend who is ordering his action today to build himself a 505 has never "put together" a rifle before either, so your comments are helping mold our thought process and planning of the rifles. Accuracey sounds very good, from a cartridge standpoint, hopefully if all goes well we can achieve similar results. Thanks again for the information.