How do I get a rifle in this caliber and where do I get ammo for it ? And does it really kick hard or is this just exaggeration? Any info would be helpful.

Hellfire,

Our host Saeed could probably answer these questions for you....

If you go to the video page, he has video clips of some of the people who have shot his T-rex, and they are a riot. His CD "The Champions" has clips of a number of people shooting this rifle. Watch them yourself and decide if it has any significant recoil, sure looks like it to me.

Rifles would be A-square or custom proposition. I think ammo used to be loaded by A-square, but not sure.

Welcome to the forum!, Bill

Unless A-Square ammo is available, you have to reload to get 577 Ty ammo.

You might find a used rifle around if you look long and hard. They are not that expensive - maybe $3K.

A more practical approach is the 585 nyati.

Recoil is dependant a fair bit on how you choose to set up a rifle of this nature. You need to keep some weight in it. 500 grains is correct in that the .585 may be an easier road to travel if starting from scratch.

I don't believe there are currently any manufacturers of the rifle. You should contact A-square as they developed the round and sold a rifle and amunition for it. I haven't heard of any other gunsmiths that built them.

The case is unique, and currently only manufactured by Dieter Hornbear in Germany. I personally can't see getting a rifle that uses such uncommon, and difficult to obtain brass.

I have never fired a 577 T-rex, but my presumption is the recoil is heavy, and there aren't alot of folks who are up to shooting such a gun. That should be tempered by the fact that most of the folks shooting the T-rex in the video's have little or no shooting experience. Dealing with recoil is simply a combination of a firm grip, and good conentration

This group is the best resource in the world for big bore enthusiasts, most any caliber you can think of, someone here likely has one. The moderator Mitch has a 577 T-rex.

I'm slightly opposed to cartridge proliferation (which is why I built .510-.505 Gibbs with no other changes), but I see the .600 Overkill cartridge as an excellent wildcatting opportunity.

If you prefer the .577 bore / .585 groove over the .600, the fine belted design of the .600 Overkill case could easily be necked down. I have considered that necking it down to .510" could also produce good results, and a cartridge that could simply rechamber a number of existing .510" rifles of slightly smaller capacity. There might be a requirement to obtain longer "basic" brass in some cases.

In short, with the relatively small premium that attaches to custom reamers (from Clymer) and dies (from CH4D) and off the shelf .600 Overkill brass from Dieter Horneber, you needn't feel confined to ordering a custom run of .577 T-Rex brass or tolerating the various reported deficiencies of the .585 Nyati cartridge design and brass from Bertram.

The T-Rex has two big problems. First the case head is too big for any action other than a Highly modified 1917 Enfield ( P14 bolt combo), a Bauska BBK-02 or a Montanna Arms Magnum PH or Prarie Gunworks magnum action. Expect to spend a minimum of $1500 on an action. Less if your willing to wait on a Montanna action.The second problem is brass as it's only available from D. Horneber in Germany and he only makes so much per run/year. No one in the US stocks it. It kicks really hard with full power loads. Few gunsmiths have any experience with it. Your best bet is to scour the used gun auctions for a A-square Hannibel in 577 T-Rex, buy it for $3500 or so then sell it when you find out just how hard it kicks.-Rob

Olympic arms make a copy of the Bauska BBK 1
$595 action only
http://www.olyarms.com/bbk.html

Rob does Montanna have a web site

[ 01-23-2003, 04:50: Message edited by: 416SW ]

416SW,<br /><br />who in Australia brings the sOLY Arms Actions in ??<br /><br />Horneber also make .585 Nyati Brass which I assume recifies the probelm that people have with Bertram. But I must say I had my smith follow Rob's chamber dimensions to the letter and as a result I have nos issues with Bertram brass at all in .585 !!<br /><br />Rob may be able to clarify for us again what he does to .585 Nyati chambers to solve this problem. It does not affect accuarcy as my friend whom also had a .585 built shot a group at 70 yards with 2 bullets practically through the same hole and one right neally touching. Funnily enough the .585 Nyati seems to be a reasonably accurate round. I can not quite shoot mine as well as my mate can shoot his. <img border="0" title="" alt="[Big Grin]" src="images/icons/grin.gif" />

416SW- I believe the BBK01 specs are different than the BBK02. I talked to Olympic arms and they could not confirm that their bolt was larger than .701. The BBK02 measures .730 on mine and thus will work with the .688 rim of a T-Rex. The 1917 Enfield has a .700 bolt, but the P-14 bolt has enough metal left on the locking lug to control the T-Rex cartridge even without any bolt rim left. BMG confirmed this for me in some pictures he sent me. Montanna Arms will be making their Magnum PH action this year and it will have a .800 bolt that will work perfectly for a T-Rex or even better the .600 Overkill 2. (3.2 inch case). They do have a website, but there is alot of discussion going on withROD@MRC on the gunsmithing board. I just placed an order for one.-Rob

Rob,

what will the price of the Montana Arms action with the .800 bolt dimater be ?? This would be the best action for the .600 OK or even the .585 Nyati wouldn't it ??

PC- I don't think they have set a price yet. I suspect under $500 for the first actions. If it all works out as planned, this is the way to go. Butch Searcy is also starting to make repro farquarsen SS actions that will take a .50BMG case. he says they will cost $4K a piece just for the action. I'm going to the reno SCI next week to look at it! Now there is the gun for a .700 BMG IMP. That makes the T-Rex, NYATI, 600 OK, etc. look like a .22.-Rob

Rob,

at that price it work out around $1000AUS to get one I think I would be silly not to buy one if I can pony up the cash.

My aim in life is to wealthy enough so I can build all these cool rifles

Rob has the .600 OK barrels from pacnor already threaded for the cz 550, if you still have those spare dies and .600 OK barrel after June I would probably like to purchase them of you, but this montana action would be the ticket for the .600 OK and that would be the way I would like to go if I build one ??

[ 01-23-2003, 05:37: Message edited by: PC ]

Rob, my Ultramag has a .720 bolt diameter. Others might be different.

Williams is also looking at bringing out a double square bridge mauser action. They said under $1K. 0.800 bolt body diameter. I am hoping that it will materialize.

500 grains- Doesn't Oly arms make a BBK01 and a BBk02. When I called they said their BBK01 was a .700 bolt and as they didn't have an 02 in house at the time they didn't know exactly what it's bolt diameter was.. Since yours is .720 thats real good to know. Do you think there is enough meat on the bolt once its opened to .693 or so for a T-Rex? Thats gonna be only about .014 of rim. I'd worry it would tear off. I opened my CZ550 bolt up to .645 for the .600 OK and the 585 NYATI. That left me with .0275 of rim and so far it has not broken off. I'm not sure I'd trust less rim. I re-hardened my bolt after machining it and so far so good. I've had a number of people say they have ripped the rims off of their Nyati's while cycling the bolt.-Rob

PC
I don't think anyone is bringing in the oly action.
Last I heard Peter of Pro-Cal still had a Bauska 02 in the white for sale $1000 AUD from memory. They apparently still need a bit of work done to them in the white state, unsure what though.
email me if you need procal phone number

Rob,

I do not know what model my ultramag is. Currently it is at Dennis' place so I can't look at the bolt with the 577 ty in mind. However, I think that .14 is too little. Personally I think that a .750 bolt should be considered minimum for a 577 ty project, and .800 would be far far better. A .700 bolt for a nyati makes me nervous, although I have not had any problem with mine.

Doesn't Ming have a bbk-01? He could measure it?

jeffe

500,

can you please expand on your statement about the .700 bolt on the .585 making you nervous why is that ?? are you afraid of the lugs shearing off ?? As you know I am inthe same boat with my .585 as is my friend.

Rob in the event of a shear off should the rim be rebated maybe not quite to the .416 Rigby case head but something between the gibbs rim and the rigby rim ?? and have some tig welding and hardening done ??

I would just pay my smith to turn my cases to this size in the event this happened and what would be the case head that would give a little more bolt rim and also still ensure postive feeding ?? Could you just take the .640 case rim back to say .600 ?? would that improve the situation.

Regards PC

Robgunbuilder!

Is it possible to build a .700 BMG IMPROVED on the montana arms magnum PH action??? How would a rifle like that look like??? So a .577 Tyrannosaur is now possible to build on that action.?

PC,

On a .700 bolt, after the bolt face is opened up for the .640 rim there is just a sliver of metal left opposite the extractor. The sliver keeps the rim in place against the extractor as the case moves up from the magazine. Since my rifle uses a single stack magazine, it does not place any pressure on the sliver and things are fine. But with a staggered feed, cartridges have a sideways movement out of the mag box and some rifles end up placing pressure on the sliver, so some of them will shear off. The solution is to get a new bolt or TIG weld, machine and re-harden your bolt.

Turning the nyati rim down further is not a good solution. The smaller rim will sit lower in your mag box and the bolt will start to override the rim and close on an empty chamber even though there is a cartridge in the magazine. This is why the 585 with a 416 rigby rim doesn't work.

500grains is absolutely right. Even with a single stack mag, a bolt with a rim with only .014 of thickness could easily shear off if even dropped once on the floor. Rebatting rims is a real bad idea. That's a one way ticket to failure to Feed land. No, to build a T-Rex, I'd wait for the Montanna, maybe spring for a Prarie gunworks or go with a modified Enfield. The other options I like are a McBros .50BMG repeater action ( Then you could move up to a 700 BMG) or a Farquarsen from Butch Searcy. Your not gonna get a .50BMG rim at .809 ( if memory serves)to go through a .805 action ring and even if you could, a 700 BMG IMP will be WAY TOO LONG for the Williams action. I suppose you could build a shortened and headswaged version, but by the time you did that it would be way to expensive and probably no better than a T-Rex.-Rob

I'd be up for 3 shots, but not 5.

500,

so your not worried about the gun blowing up then just the metal around the rim of the bolt ??

My .585 has such a small stagger that it is almost a single stack. I have spoken to my smith and he said he doubted that it would ever give any problems but in the event it did he could fix it. I realise turning down to the rigby rim would be a prooblem but what about just turning it down from say .640" to even .620" would that make all the difference with feeding and give a tad more metal ??

I think I would like to build a second .585 on this montana action so that I could have everthing just perfect, infact I would like to have a pair of them to do a .585 & .600 OK.

PC, the rifle will not blow up. It's just a matter of that little sliver breaking off and then not holding the round against the extractor.

PC without that little rim the round has nothing to stop it's upward travel on feeding and nothing to hold it on extraction/ejection. -Rob

And if that happens at the wrong time Rob you get stomped.....

what do you think about rebating the rim to say .620 that gives a little more metal on the bolt face, and would it still feed right ??

PC- I would not do it. Severly Rebatted rims are always a problem with reliable feeding! You have a CZ602 right. Your bolt is a .700 and the NYATI rim is .640. You have a .030 rim and if your Smith hardened the bolt after opening it up, you should have no problems. It's only when you get below .020 that the rim becomes so paper thin that it's liable to tear off.
This is why you just can't build a T-Rex on any old .700 action. Make Sense?-Rob

Thanks Rob I am with you now !!

My smith followed your instructions to the letter and as a consequence Bertram Brass gives me no issues at all

I ordered a 577 Tirano accion from Truvelo a few months ago for about 1400 Euros. A few days ago they informed me that the accion was ready and they were proofing it. After this I changed my order to a complete rifle and they told to expect delivery the next two or three months. They made a bigger accion on request.
You can find more information about it under www.truvelo.de/truvelo.
I hope this may be of some interest for you.

Bongo