My brother brought a Tarus Ti. 41 tracker to play with. 4 inch ported

He also brought a box of 210 speer jsps. The following vel were taken at 10 feet in front of the muzzle.

H110 21grs
avg vel 1049fps

Blue dot 13.5 grs
1156fps to hot cases had to be pounded out of the cly.

2400 17.5 grs
1069

The books list vel from 1300 to over 1400 as one can see nothing even close to book vel. These were all max or very near max out of the books.

With vel's like these this 41mag leaves a lot wanting. I have read of a lot higher vel's from other 41 owners. But this one doesn't.

Any thoughts

First pdog, the only 210grjsp I know that Speer makes is their 220grSWCJSP . That could be part of the problem. The vel. you are listing from a 4" ported bbl. are pretty close to what you would expect from those powders. You'll need to go to H110 or W296 to get the vel. up w/o the pressure. Also, the long jacket of the Speer SWC will raise pressures a bit over a Sierra or Hornady of the same weight (longer bearing surface).
BTW, the #13 Speer manual shows 11.4gr max. for BlueDot @ 1203fps from a 6"bbl. 15.8gr of 2400 for 1215fps w/ 220grJSP. I know the Alliant site shows higher but bullets do matter. I have fired 11.0gr BD from my 4" M57 but I didn't chrono it. Pressures seemed normal. Also, Taurus can be rough, you may try polishing the cylinders, but don't expect much more than 1200fps from a 4" gun, maybe 1250fps w/ H110. Good luck.

My Blackhawk 41Mag has a 6 1/2" barrel and using 20.5 grains of H110 which is .5 under max published load in my Sierra manual chronos at 1335 ft/sec with a 210JSP. Longer barrels on large bore revolvers obtain a lot of velocity compared to the shorter ones. I wish I could have bought mine with a 7 1/2" but it is no longer offered.

Luckyducker is right. You can get another 100 fps from another inch of barrel, more or less.