Looking at the massive .680 rim on the trex . I know it won't fit standard long actions. And I'm thinking of building a .550 mag on a mark v.
But for curiosity .would a 577 tyran fit a 408 action. Stiller makes a 408 tactical can be had in 1.45 or 1.60 diameter. Opening the bolt up shouldn't be a problem perhaps. But I don't know who could come up with a internal magazine for such a action. Which is why I'm leaning towards the .550 on a mark v the may already works and its there. Plus brass doesn't have to be special ordered.

I'd find a supply of 577 T-Rex brass before I went down that road. Good luck with that!!!

When i load 600gr rn bullets out as far as they go in my MKV 510 wells, it can bind a bit going in the chamber. I know i can adjust the feed lips a bit and it would solve the issue but it got me thinking that a 550 might need a little extra work. Especially for the 3".

577 t Rex brass is extremely hard to find right now.

Is that not an opportunity for someone who has the skill/equipment to make this brass? 505 Gibbs and many others have always been hard to get but in recent years that has come to pass. Surely, it is because someone seen the $$ opportunity.

Well the Mark v box is 3.815. The .550 with a 800gr hawk rn is 3.835. So it won't work with that bullet.but all other bullets 600-700gr are loaded from 3.715-3.790" . Weather by drop box kit is suppose to Max the mag open up to 3.850".
How about a 577 nitro express in a 408 action. I see heym is offering it in their new rifles. Its a .748 rim


The .550 can be loaded even shorter like 3.4-3.5. With hard cast bullets around 800gr .
There's a guy on here with a Mark v in 585 nyati.

Woodrow-- The problem is that guys doing Trex cases want
6 bucks per case. It is a pain in ass to make

On of the reasons the big increase in the supply of
Gibbs brass is the demand for Cheytac cases, as all the same
draws,dies, and punches are used except last one, the header, from
same brass cup blanks. SO Bertram now and Jamison
when he was operating made Gibbs while making Cheytac.
And he will be using same deal to make my 585HE run
using a different header for our case, being run
soon this summer. Sending funds this week for part of
it and more in couple weeks. 3 bucks a case if you
get in on the initial run..

You know a Gibbs/Cheytac size action like the MRC PH,
the big CZ, the Big Rugers, as well as many other
styles can do my 585HE. FBW and Ruger falling blocks,
anything that handles Gibbs/Cheytac will do.
I have them in a BBK, a Savage, a Mauser,
monoblocked in shotgun actions.
Get in on the case run and you won't have to worry
about brass, as Bertram makes these draws and runs
every month now,an ongoing Cheytac order, and will just
finish the 3 different case heads with header changes
during the case runs..

So we can make orders quite often.Here is pic
of my 585HE showing it fits wherever Gibbs fits.
And I have it in 3 Enfields, an early Ruger.Soon have it in
A Mk5, a Greener-Martini, Beretta 10ga frame.
I have it in break action 10ga frame NEF where
I load it to outrun a Trex factory loads..Ed

I made a new thread. Is a 577 nitro express rimless a viable wildcat idea for a bolt action?

.577 TRex brass is extinct! What's out there sucks. no one who knows what they are doing will fool with it. I owned a .577 TRex and frankly it was unimpressive. Best of luck with your project.-Rob

Defiance Machine makes nice 408 actions too.

Going to go with a .550 mag in a cz action

AHR's and Weatherby's single stack magazine boxes fix most feeding issues with large cartridges.

would gladly pay 6.00 each for some good t rex brass

I can put two Sav 06 mags together
and make long single stack for my 585HE.

Getting good cases is a plus, and getting mine for
decent price, with them being made to same high
pressure specs as hot loaded Cheytac cases, a real plus..
He is using the same cup blanks and drawing equipment,
inside punches, etc. Cases will have same thick base.

A way of looking at it is, maybe try my 3 buck
wonder case in a gun? As they can outrun a Trex
in the two I have monoblocked in NEFs(and bolt
guns and FB faster) An ole NEF... Join in and have fun.
I have done over a dozen guns in building/experimenting,
in about 8 styles of guns in my 585HE, all for less than
than fancy trex cost at a big shop. Ed

Bigdoggy- There is no good Trex brass. I sold my Trex and 100 pieces of nice new sticky brass for a small fortune and constantly have to deal with the guy I sold it to complaining about why he has to hammer the bolt open with hot loads and where he's gonna get more brass once the stuff he's got splits.-Rob

585he is where its at whens it comes to a 577 bolt gun. Trex actually not that impressive
It only shootz a 50gr heavier bullet comparrd to the .55 mag @2400 fps

quote:

Originally posted by Zebrapunch:
585he is where its at whens it comes to a 577 bolt gun. Trex actually not that impressive
It only shootz a 50gr heavier bullet comparrd to the .55 mag @2400 fps

So Zebrapunch, are you going to do a 585 HE?
I think that is a very cool, exciting round!!!

quote:

Originally posted by Robgunbuilder:
.577 TRex brass is extinct! What's out there sucks. no one who knows what they are doing will fool with it. I owned a .577 TRex and frankly it was unimpressive. Best of luck with your project.-Rob

Well Rob, respect your opinion, but I musk frankly admit that it has impressed me... - it works flawlessly and brass (from Horneber) is perfect, I got a 500 pcs of brass supply, so never have to worry...

I get 750 grainers at 2600 fps and 800 grainers at 2500.. Not bad, and effect on game have to be seen to be understood..

Buff- I think a lot of my dislike for the TREX comes from the interactions I had with A -Square and Art Alpin. Just getting rid of it seemed to eliminate a certain stench related to its originators. I never had any Horneber brass just asquare and Bertram crap. Anything over 2500 fps stuck so hard a hammer was needed to open the bolt. Best gun deal I ever made when I sold it but the new owner constantly complains about it.-Rob