10mmjunkie Posted October 3, 2011 Share Posted October 3, 2011 Am considering converting my 40 S&W EAA Match to 357 Sig. Has anyone done this and are there any special considerations to doing so? Does anyone make a barrel in this caliber (EAA does not)? Use this caliber in several of my Sigs and have found it very flat shooting, moderate in recoil and has very low extreme spread in velocity. Being accurate and 20% lower cost in bullets (vs 40) does not hurt either. The only draw back to the caliber is it is loud. Any information is much appreciated. Respectfully, JW Link to comment Share on other sites More sharing options...
bikerburgess Posted October 3, 2011 Share Posted October 3, 2011 there are very few after market barrels avaliable for Witnesses I think your best bet would be to get a factoryo 9mm barrel from EAA and have it reamed to 357 sig. the only other issue I could see coming up would be if there are any feed issues with the magazines, you could do a simple test and hand cycle a few mags throught your 40 barrel. If I recall correctly I had some nose dive issues when I tried this test with my old 10mm magazines, you may have different results depending on which type of mag you are running. One other thing to remember it will be a fun gun but you would be limited to shooting minor in USPSA as 40 is the minimum caliber for major in all divisions but Open and Revolver. Mike Link to comment Share on other sites More sharing options...
david s Posted October 3, 2011 Share Posted October 3, 2011 Jim Milks at Innovative Custom Guns has just reamed(last 30 days) two Match 9mm's to 9x23 Winchester so he could handle any conversion work you needed. Jim@innovativecustomguns.com Call after 1pm. 814-766-3004 Are you sure the .40 new K40 mags will run 357Sig? In the case of the 9x23 we just run new K38 Super mags. 21+1. Mags got to run the ammo because it's gets ugly when they don't. Link to comment Share on other sites More sharing options...
10mmjunkie Posted October 10, 2011 Author Share Posted October 10, 2011 Thanks to all. I do not shoot USPSA but Steel Matches. Flat shooting and knocking over plates are all that count. 9mm will not always do that and even light 357 Sig will with less recoil than 40, not to mention cheaper bullets. Will see about getting a 9mm barrel from EAA. Respectfully, JW Link to comment Share on other sites More sharing options...
shabodah Posted October 15, 2011 Share Posted October 15, 2011 Actually, Hennings lists a 357 sig conversion kit on his site as well. Link to comment Share on other sites More sharing options...
Joe4d Posted October 15, 2011 Share Posted October 15, 2011 What do you mean by flat shooting ? If you are talking trajectory I dont see any practical difference between a 40 and 357 sig at hand gun ranges. i don't know your requirements though are you shooting 100 yards like in silhouette shooting ? If you are talking slide movement, again I cant fathom any difference, in fact I would expect more muzzle rise from the 357 sig. Bullet cost is a wash, you can use heavier moly bullets in 40 vs the jacketed bullets needed for the higher velocity light bullets. If you are using 130-147 gr cast in your sig again bullet cost is a wash. Especially if you consider how many bullets you can buy for the cost of a 357 sig conversion and custom reaming. Recoil is gonna be a factor of bullet weight, powder selection, charge weight and velocity and bore size. None of those favor the 357 sig loaded to the same power factors. There's no capacity advantage with a 357 sig. In short there is nothing a 357 sig can do a 40 cant. Except comply with some laws in certain areas, and I did meet one guy doing this that got free 357 sig ammo, but other than that or something I havenmt thought of I see no practical reason for doing it and lots of reasons not to, Saying that I have a gunsafe full of unpracticle guns that I really enjoy, and I like having unique firearms. Variety is the spice of life. easiest route would be a 9mm barrel and a 357 sig reamer and go/nogo gauge. Link to comment Share on other sites More sharing options...
n5esrx Posted January 13, 2015 Share Posted January 13, 2015 As stated by others, best to pick up a 9mm Tanfo barrel and rechamber. As far as the .357 SIG not having advantages over the .40 , I strongly disagree. I have run .357 SIG in a number of SIG Classic platforms for the past 6 years. Not only are the terminal ballistics better than the .40, it has more accurate, has less muzzle flip, and flatter trajectory. In fact, I have rid myself of every .40 barrel that I have. I also EDC the .357 SIG, something I would not do with the .40 . I am about to do the same conversion with my Witness Classic, though I have yet to decide if I am going with .357 SIG or 9X25 Dillon. I have reamers and headspace gauges for both... so I will probably try .357 SIG first and see how the pistol likes it. Link to comment Share on other sites More sharing options...
USAFA82 Posted February 17, 2015 Share Posted February 17, 2015 n5esrx, Is your Witness Classic a Small/Narrow frame Tanfoglio? Have you done this conversion yet? If so, how well does it shoot? Thanks! Link to comment Share on other sites More sharing options...
jmbaccolyte Posted February 18, 2015 Share Posted February 18, 2015 (edited) I agree with Joe4d. Also to the OP, because of your screen name- My Match accepts .40 S&W cartridges loaded at 1.25" O.A.L. [with the K-10 (10mm)] mags (with Bayou and BBI coated bullets) and feeds flawlessly. I'd play around with a fairly fast powder to get however much velocity you need to knock down the steel plates. The plates I've shot seem to prefer 180 grain bullets at moderate velocities and the distances haven't been long enough to make the bullet trajectory an issue. Just sight it in at the most common distance and practice a lot. Just my two cents. Edited February 18, 2015 by jmbaccolyte Link to comment Share on other sites More sharing options...
BeerBaron Posted February 18, 2015 Share Posted February 18, 2015 n5esrx, 4 year old thread.... I know you're passionate about the sig but I'm sure everyone above has moved on by now. Link to comment Share on other sites More sharing options...
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