There are, so far as I am aware, four of the Beristain, S. A. side lock guns up for sale just now:
Bufalo Arms (Beristain, S. A. [Spain]) , FULL SIDELOCK SIDE X SIDE, Model No. 57, 12 gauge (2 3/4" chambers) Sale priced at $1495.00
http://www.gunsinternational.com/guns-fo...un_id=100574312Beristain Buffalo M57, 12 GA Price: Was $1599.99 Now 999.66
http://www.gunsinternational.com/guns-fo...un_id=100563568Spanish Beristain Sidelock extractor 12 double Started at$1,000.00 No Reserve (made by Industrias Ilja - Kyrie)
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=496026181Beristain Spanish Sidelock ejector 12 Started at $1,200.00 No Reserve (made by Armas Parkemy; A. P. M. - Kyrie)
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=495753640 All of these guns look to me like tax salvage guns, and may have been prettied up or otherwise altered by whomever their previous American owner may have been. IMO the one made by Industrias Ilja (GB # 496026181) is the best value for the money.
Purely FYI, there were two Beristains in the shotgun business; Beristain y Cia and Beristain, SA. Beristain, SA was a gun retailer (like Orvis, Stoeger, Denton and Kennel , Trust Eibarres, etc.) rather than a gun maker, and sold guns made by the Basque gun makers under his own name. The guns above on Gun Broker have pictures that show the names of the gun makers who actually produced the guns.
Back in the day these guns were made they filled the same market niche that the Garbi 100, Arrieta 577, AyA No. 2, etc. fill today.
If a fellow were pursuing value, this is a gun worth looking at:
Arbemarle # 1 double SxS, .20 ga.-Sidelock- NEW Buy Now for $1,785.00
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494547425 The seller wants more for it than Im willing to pay, but its a gun worth considering.
These next two guns are sleepers. Both of these guns, at the time they were made, were THE top price point gun cataloged by the maker. The amount and high skill level of work that went into the engraving of these guns make them effectively economically impossible to produce today.
ARMAS EGO SPECIAL MODEL SIDELOCK EJECTOR SXS 12 GAUGE Price: $3,500.00
http://www.gunsinternational.com/guns-fo...un_id=100554433ARRIETA BEST QUALITY SXS 12 GAUGE Price: $3,950.00
http://www.gunsinternational.com/guns-fo...un_id=100563550 Again, the sellers want more than Im willing to pay, but the gun are worth drooling over.
