The only two time I have used a action wrench was one time I purchased a Krag for 50 dollars and I took the barrel off so I could part the gun out minus the action ... And the other time I purchased a action at the gun show and then purchased a original barrel on eBay .. and .... Screwed it back on the action and it fit perfectly and the head space was exactly on ... This was because krags are very precision made although when you put a barrel on a action there are 800 things that can wrong so you really need a very good gunsmith who has Krag tools and can do a good job...