Building a 50 BMG
- Thread starter schoots
- Start date
- Location
- calgary alberta
Anything for 50BMG is not legally exportable from the USA. Bats do look nice but are incredibly soft and very prone to gauling. Any Bat that comes to our shop is carefully inspected when it arrives for gauled lugs and other damage before anyone touches it.
I have plans for a box/gill type brake. Could take photos of the basic parts. There are two lathe turned pieces - the collar that threads onto the barrel, and the muzzle cone. There are top and bottom plates, and a number of baffles. These key together and are then welded. Looks not unlike the Steyr.
- Location
- calgary alberta
Why would you want a terribly inefficient and abusive brake?
Ask around and likely you will find someone MORE than willing to sell you the brake that is left over from 1 of the Steyr rifles that we supplied a VERY efficient brake for.
Most guys want LESS recoil and ALOT less blow back of gasses in their faces than what the Steyr and Armalite brakes deliver to the shooter every time they fire the gun.
- Location
- calgary alberta
Bruce builds a gorgeous action, but I agree with Ian 17-4 stainless is quite soft and DOES tend to gall easier and worse than other steels that are used.
Nesika had a run of actions ade of 17-4 and we had to have several of them replaced for galling.
- Location
- calgary alberta
Yes we are but a scope rail does not have many moving parts so normally galling of a scope rail is not an issue. Nor does a scope rail need to work under the 60000 PSI operating pressures as some calibers can create, so I think it may be safe to make a scope rail out of 17-4 stainless.
greenpasture, why don't you go back and read that thread, rick simply said his rails made from 17-4 cost more than 6061 rails because of material cost and the fact stainless is harder on tooling. then he went on to say his stainless rails were a lot stronger than aluminum. no where in that thread do i see him speaking highly of 17-4 he simply stated its stronger and harder to machine than aluminum which quickly learned if you spend any time at all in a machine shop.
now i know this is a hard concept to grasp ill try to explain it but if you don't understand i'm sure you can order machinery's handbook and technology of machine tools.
stainless like aluminum, titanium, and other alloys that generate an oxide layer typically gall more than carbon steel. some alloys like 17-4 are more susceptible than others.
now if you call the fine folks over at carpenter technologies they will tell you this is cold welding, and they are the people to talk to about it because they deal with it every day in stainless steel fasteners and bolt closing and the lugs making contact is the exact same motion that causes galling in carpenter tech's fasteners.
now if you want to continue ricks rails are chemically blackened so they don't have two pieces of stainless in direct contact with each other, there is a protective layer because of the blackening process.
if you want to go around trolling at least read a book first.
Galling and wear are failure modes that require special attention with stainless steels because these materials serve in many harsh environments. They often operate, for example, at high temperatures, in food-contact applications, and where access is limited. Such restrictions prevent the use of lubricants, leading to metal-to-metal contact -- a condition that promotes galling and accelerated wear.
In a sliding-wear situation, a galling failure mode occurs first, followed by dimensional loss due to wear, which is, in turn, usually followed by corrosion. Galling is a severe form of adhesive wear that shows up as torn areas of the metal surface. Galling can be minimized by decreasing contact stresses or by the use of protective surface layers such as lubricants (where acceptable), weld overlays, platings, and nitrided or carburized surface treatments.
Test results from stainless-steel couples (table) indicate the relatively poor galling resistance of austenitic grades and even alloy 17-4 PH, despite its high hardness. Among the standard grades, only AISI 416 and 440C performed well. Good to excellent galling resistance was demonstrated by Armco's Nitronic 32 and 60 alloys (the latter were developed specifically for antigalling service).
now maybe you should be the one emailing varmint al because the only thing i seen looking at the link you provided was a basic load analysis which would indicate deformation and stress at X psi none of the models done on his page would show information about galling and oxide formation but you would know this if you had done any CAD modeling but no you just run out and look for the first thing that looks overly technical to someone such as yourself then try to slap it in ricks face and make a snide remark that Al would be happy to help rick if he didn't understand it when in reality reading and understanding those models is quite a simple task for anyone thats done basic CAD / 3d modeling. to be honest its pretty tiring seeing someone attack guys like rick and ian with any knowledge of metal or CAD and with out bothering to do even the most basic research.
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You might consider not running your mouth off with generalities. Of course you obviously think you know it all anyway.. clearly not the case.
As for the base, of course ATR has stated it is coated.. MOST RINGS are coated as well, but dah... coatings do break down and in some cases they are not used.
You might use your brain and try to apply the verbage you copiedand simply spewed like parrot.
If you think that information is CAD you are sadly mistaken. It is a specific engineering program but its obvious you don't have a clue! Couldn't find that info in a handbook could you.
If you investigated other sources you would find and learn more.
What the hell does CAD have to do with anything? If CAD were used to model the forces, it would show the forces the rail were subjected to are insufficient to produce galling? Is that what ifconfig was trying to say? I don't know because what he said at the end didn't make a lot of sense.
The truth is, the coating is likely for looks more than galling prevention. I don't see how it's an issue with a rail. I suspect that any 'galling' you're seeing on a rail is likely a deformation process rather than a transfer process. The forces at play are not even in the ballpark to cause galling.
The bolt and receiver are another matter altogether. Scope rails - I suspect you'd shear some fasteners long before.
You might consider not running your mouth off with generalities. Of course you obviously think you know it all anyway.. clearly not the case.
As for the base, of course ATR has stated it is coated.. MOST RINGS are coated as well, but dah... coatings do break down and in some cases they are not used.
You might use your brain and try to apply the verbage you copied
If you think that information is CAD you are sadly mistaken. It is a specific engineering program but its obvious you don't have a clue! Couldn't find that info in a handbook could you.
If you investigated other sources you would find and learn more.
ok ill take the time to make this extremely simple.
1. when a base and ring are secured there shouldn't be any movement
2. the chemical blackening process applied to the base will provide protection even if uncoated 17-4 stainless rings are used.
3. stainless steel galling typically occurs when two parts of the same alloy are in contact with each other
so at the end of the day the ATRS base is very unlikely to gall.
4. if you call quoting a source "parroting" then i guess im guilty of that however wouldn't quoting varmint al be the exact same thing ? the difference is i understood the information i was presenting.
5. its well documented that two mating surfaces both made out of 17-4ph provide poor wear and galling resistance, which is why you never see fasteners, valves, etc parts made only out of 17-4, in the case of a fastener the bolt is typically 17-4 and the nut is 18-8 this is because it reduces the chance of galling. feel free to call spirax-sarco and ask them.
6. i guess i should make it a little more clear. LS-DYNA is FEA however it requires a CAD model, now i know you don't like reading so ill post the definitions for you:
CAD: Computer-aided design (CAD) is the use of computer technology for the design of objects, real or virtual.
Finite Element Analysis. When a surface model is subjected to various tests to determine or establish its integrity under specified conditions.
so to even do the stress analysis you need to CAD the model first, some of the better packages like solidworks/cosmosworks are CAD integrated FEA, meaning you can go do your analysis in the same suite but you knew that already right ?
7. when doing a FEA model the conditions are very specific such as Al's test he was looking at deformation at 60,000 psi his model wasn't designed and was never meant to be a repeated wear analysis which would show evidence of galling. to expand on this even more Al's models don't factor rotational wear on the lugs because all his model simulates is X surface ( bolt lugs ) mating to Y surface ( action ) with stress on the Z surface ( bolt face ). so for Al to say anything about galling based on his model would be out of the question and for you to imply it is sheer ignorance.
and after going over your short post history i see about 5 or 6 threads making up at least 1/3rd of all your posts and these are all trolling ATRS. now that says something doesn't it.
thebigside, sorry i wrote that at 4am,
anyways greenpasture posted a link to varmint Al's page where Al did a stress analysis of a bat 17-4 action with a cartridge pressure of 60,000 psi which is where the CAD/FEA subject came up.
and your correct the coating is most likely for looks but it will provide some galling protection and again your correct about any wear on the rail being caused deformation rather than transfer
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