I purchased a lightly used ruger Vaquero .44 mag last February at what I thought was a great price and with the first firing realized that it was hitting 9" to the left at 25yds and patterning like a cheap shotgun. Sent it back to ruger and no problem, it came back with the windage corrected no charge but in several months of load development (cast & jacketed) can't get it to hold better than 7" at 25yds with any load. I have not slugged the barrel but I did find that the throats are .433 dia but consistent. The largest cast bullets I could find are .432 and are still loose in tne throats and i would'nt want to go any larger anyways due to the probable groove diameter. any suggestions of what to do short of having a new cylinder fit for more than the cost of the origional gun?
Thanks in advance,
Joe

If you want to shoot cast, go with heavy gas checked bullets, sized 0.432".

Jacketed bullets should not be an issue. I have a S&W with 0.433"+ throats and it shot well (3" at 50 yards) with jacketed.

It makes me wonder if something else is wrong.

The best solution is to buy a mould that drops bullets larger than .433" and cast your own bullets. If you don't want to go that route, there are custom casters out there. There's a guy in Alaska that runs The Bull Shop, which advertises custom cast bullets in "any diameter, any weight, any style". The URL is below.

The Bull Shop

I don't think the throats are a problem. My 480 Ruger has .478" throats, .475" bore, and I've been able to get 1" 50 yd groups with most cast bullets I've dialed in a load.

But, I do have an old model 357 blackhawk that shoots like yours, and I've tried about a dozen different bullets, cast hard, soft, big, small, push em hard, push em easy, darn thing won't shoot.

So I finally put a slug down the bore and found the barrel has a tight contriction where the barrel screws into the frame. I started lapping it out, and haven't gotten quite done yet. Last range session the groups were cut in half. What I plan to do is bore a Taylor throat in the barrel and some other tune up stuff, but I haven't had time to do that.

I'd be quessing your gun suffers from the same bore constriction.

Thanks all for the info I think the barrel might be the problem also I checked the basepin today it is about .2475 and the center hole in the cylinder will take a .2505 gauge pin so I think my next step will be to order a belt mountain oversize basepin and a fire lapping kit from beartooth(or elsewhere, if anyone has any good experience with others please let me know) and then get some 250gr .432" cast & give the load development another go. also if anyone has any experience with titegroup in 240 to 250 grain .44mag cast gc let me know, up to this point I have only used it at 6gr behind a lighter 200gr rn flat point plain base with very good results (and cheap!) but I have not found alot of info for the heavier gas checked bullets so I have stayed with H110

Thanks Again,
Joe

By heavy I meant 280+ grains. 250 gr. is not heavy. 200 gr. is definitely not heavy. The longer, heavier bullets are more forgiving.

You may run into other problems if you try to load throat sized bullets, i.e., case neck OD too big, rounds will not fit in seating die, that's why I suggested 0.432".

I had not considered a barrel constriction since I have 3 Ruger single actions and all had dimensionally good bores from the factory. But that could definitely cause the problem you described. The only lap kit I've ever used is the LBT available from Veral Smith and I've been very satisfied with the results.

First, I would not worry about the throats that much. My SBH has the same size throats with a .430 bore. I use .430 boolits and have had many 100 yd groups close to 1". I use 320 to 330 gr boolits with 21.5 gr's of 296. The gun does not like anything lighter the 240 gr's.
Next thing to do is to toss the magnum primers. The .44 does not like them. Use Fed 150's. I have spent years testing primers and in every case groups tripled with magnums.
The only Ruger that likes H110 is the standard Redhawk. All others shoot better with 296.
A barrel constriction will give you trouble but the newer guns are not bad. You can feel it if it is there with a tight patch and jag. Don't use a slotted rod end, you can't even clean the bore with them. Power lapping will remove any constriction.
My SBH has way over 57,000 heavy loads through it and will still group an inch or less at 50 yd's.
Throat problems are when they are smaller then the bore. Ruger made a lot of .45 Colts that way. You can live with a larger throat.
Try the Lee 310 gr or the LBT WLNGC 320 gr.
Next thing that is suspect is your shooting itself.

bfrshooter: thank you for your almighty wisdom if you say that it is my shooting you must be right, I've seen your condacending comments on about every thread on this site so you must know what you're talking about(or maybe you have nothing better to do with your time) but anyways I guess I'll just sell all my guns and give up shooting or maybe I'll take a drive down to WV to watch the master shoot 1" groups at 100yds with his super blackhawk and learn a thing or two

I have been shooting the .44 mag since 1956. I have put more lead and bullets through them then you ever knew existed. If you think I am being condescending, you are wrong. I try to pass on my experience but see some of you know more about the gun then I do to the point that you will not even try some of my suggestions. I have never said that my way was the only way, only to try something different instead of hanging on the loading manuals and other written jargon. Nothing worse then someone that has thrown 50 rounds downrange and is suddenly an expert. I am content to let you struggle, no skin off my back. Sell the gun or buy a custom cylinder. When you have the same problems, don't ask any more. Figure it out yourself.