I'm getting a MRC 1999 gun put together in 7X57 for my left handed son. Not a lot of gun to choose in LH 7X57. His gun will come in a 1 in 9.5 or 10 twist barrel. Looking to shoot 140 grain loads for deer mostly. So I was thinking about getting a CZ American 550 in same caliber. Was wondering if anybody would know the twist in this gun barrel. I heard somewhere the shoot 160's better than the 140's. It wouldn't make that much differance but was just wondering.

I own a CZ 550 American in 7x57mm. It has a 1x8.66 twist barrel and is suited for the heavier 7mm bullets. I shoot the Hornady 162 SST in mine. The CZ has a very, very, very long throat. My rifle favors the bullets being .01 inch off the lands, however, there are only two 160 grain bullets and no 175 grain bullets that I know of which will seat .01 inch off the lands and still have enough bullet shank to fit and stick in the case mouth. The 160 gr. Nosler Partition is one, the Hornady 162 grain SST is the other. You'd think that with another 15 grains, the 175 grain bullet would be a better choice, but it just won't fill the bill. Only in my CZ, I load 48.9 grains of H414, the 162 grain SST Hornady, Remington cases, Federal 210 primers and seat the bullet .01 inch from the lands. The overall length is like 3.295 inches or so, but this puppy with sandbag rests will put three into .481 inches easy. I once got a .216 inch group. The load chronographs at 2,855 fps, which, for a caliber developed in 1892, isn't too shabby. I use it for elk, mule deer, antelope, wild pig, coyote and just about everything between. If you are even thinking about using this load, I'd drop it by 10 percent powder charge and work up. The CZ is one hell of a rifle, and the 7x57mm is one great little round. Tom Purdom

That long throat seems to hold in all of the CZ rifles. I have a 527 in 22 Hornet that has a throat so long I can put a loaded round in it that won't go in the mag and still not touch the rifling. That keeps the pressure down when I touch off 13 gr of 296. Heh Heh

7 X 57:

I would recommend that you try the 160g Barnes or the 150g Scirroco. They are both very long for their weight and should be able to be seated out to your lands. I don't have any experience with them on tough game like elk, but I think either one would do the job. The Scirroco seems to be a pretty accurate bullet, the Barnes a little more finicky...

Just a thought.

MKane160 aka BigDogMK

7x57MM Thanks for the information. I was wondering what if anthing you did for bedding. I know you did a lot of work on the gun itself. What kind of group sizes were you getting with lighter bullets. 1/2 inch is great but I could get by with 1 1/2 inch if I could make them work in both guns. ( Whitetail deer 200 yds or less ) Thanks again I'm quite sure I will be looking for one.

257 Rock: I glassbedded the action and about one and one-half inch of the chamber area with a glassbedding kit from a gunsmith in Albuquerque. It allows you 90 minutes of work time and is very solid stuff. Can be found at www.scorehi.com on the internet. The four ounce kit is more than enough. I also made sure the barrel was freefloated so I can slip at least two new $20 bills between the barrel and barrel channel up to the area I glassbedded. I was using about the same load in a Ruger Mark II in 7x57mm so when I got the CZ, I loaded down a tad and then brought it back up to 48.9 grains. My rifle takes about nine fouling shots with three, three-shot groups going into about 1.25 inches then it just clicks into the sub-half minute groups. I have not even tried lighter bullets yet. I have some, but am waiting for the weather to get a bit better before venture out again. Tom Purdom

7x57 Thanks I think i'll be looking for one shortly. The weather is not very nice for shooting here right now. Isn't getting above 0 for the last few days might be better next month 2 or 3 months for sure. Maybe we will have both gun by then.

I recently purchased a mod 550 in 7x57. My first shooting session showed some wild groups. Realized I had stock to barrel interferrence at the last 1/2 " from end of forearm. The pressure was pushing the barrel from left to right.

Removed the slight amount of wood in the forearm channel.

Now with the action screws tight, two paper dollars would slide down nicely. Back to the range with Federal 140 gr.

( the cheap stuff ) Three shot groups were going .8 to 1.0"

in a nice triangle shape. Georgia Arms 140 gr ballistic tips were about 1.0 " Note: during this shooting session I was doing a LOT of barrel cleaning and I am still getting used to this new rifle / trigger. More shooting needs to be done to know for sure it's capabilities. Will try 160 gr next .