...this is/was published elsewhere on public forum...so just pasting it here for a library reference for others to read through... http://field-target.mforos.com/931594/7924845-drum-leupys-custom-shop/ Interesting read, especially technical stuff ! Date: 2009 " Hello XXXXX and thanks for getting in touch. I've re-barreled a lot of Steyr LG110 guns now with BSA barrels, and every time an improvement in accuracy has been noted by owners. These have all been for the target shooting fraternity who operate at power levels around 11 fpe. I agree with you that reducing the muzzle report does help accuracy as it improves concentration, but the best muzzle attachment is an air stripper. This reduces turbulence at the muzzle which increases pellet stability and accuracy, and a moderator to some extent does the same. I almost exclusively use hammer forged BSA barrels for re-barrelling PCPs, as in my view these offer the best quality and are superior to the likes of button rifled Walther or HW in linearity, choke quality, rifling, pellet fit, and ultimately accuracy. BSA barrels however are slightly undersized in diameter to fit most action blocks correctly including the Steyr, so the diameter has to be bulked up. As with all barrels, there is usually a discrepancy between the bore and the outer diameter of the barrel, which is basically a lack of concentricity known as run-out. This is probably also present on your existing barrel, which further adds accuracy errors quite apart from bore quality or barrel bends. Poor concentricity or run out happens because long hole boring is a technically difficult process, and barrels are seldom concentrically bored as a result. This is further exacerbated by the grinding process and can be a problem because it's the barrel periphery that acts as the alignment register in the action block. If this run-out is present and isn't corrected, this gives a misalignment between the bore, i.e. the ballistic curve, and your optical sightline, giving varying POI accuracy at different ranges. The answer to this is sleeving, which at a stroke bulks up the barrel diameter for correct action block fit and completely removes peripheral run out. So the first action is preparing the barrel for a sleeve, for which I turn the barrel breech end down to a smooth parallel section which is perfectly concentric with the bore, and then prepare a finely finished oil blued polished steel sleeve, which is a very tight fit, to go over this. This tight fitting sleeve is additionally held onto the barrel spigot with Locktite, so is a permanent fixture, and I also give this a location register, to allow easy barrel stripdown and refitting in the same position. The outcome of this is that it improves bore/sightline concentricity, probe alignment and action block fit. The barrel is also slimmer than normal at the forend of the frame so the annulus free-floating clearance is greater. There is a lot of work involved in sleeving, and it's pretty much essential that you have it. This however is not a cheap exercise and costs would be something like the following: New parallel ground, blued and choked BSA barrel blank up to 24 inches* in length XXXX. (Please confirm length and calibre required). Reduce to required length and crown with polished 11 ° target crown XXXX. Screw cut muzzle half inch UNF for moderator or air stripper attachment (if required), XXXX. Black delrin thread protector ring inclusive or custom made oil blued steel or aluminium thread protector ring XXXX extra. Prepare and fit oil blued and jewelled sleeve at breech end to improve bore/sightline concentricity, probe alignment and action block fit, XXXX. Provide alignment register**, crown at breech, prepare breech lead-in and profile detail XXXX. RFD transfer (required under the new VCR legislation in the UK) fee at my end for new barrel XXXX. Return International recorded delivery postage at cost, say XXXX. *If you're deliberating over barrel length, I would suggest you move from the 450 mm original length to perhaps 500 mm. PCPs always benefit from long barrels which will give you better pneumatic efficiency. This in turn will allow you to reduce the regulator output for the same fps at the muzzle which has benefits not just of air economy but better consistency due to the lower volumetric transfer. However if you choose not to do this please be aware that the increase barrel length will increase the power output of the gun. Target rifles like the Steyr are usually always run well under the legal limit for best accuracy, and here are some calculations with the new barrel length you might be interested in. .... With the original 450 mm length barrel Crosman Premiers average 754 fps equivalent to roughly 230 m per second. This equates to a pellet dwell time in the barrel of 1.96 milliseconds (ms). A new 500 mm length barrel at the same regulator output will give 793 fps, equivalent to roughly 242 m per second, equating to a pellet dwell time of 2.06 ms. The new longer barrel will therefore give 0.1 millisecond extra dwell time, and although this is an incredibly short space of time you should endeavour to allow your shot follow through to reflect this. At higher outputs, this time interval be even shorter. **I provide an alignment register because the Steyr breech has no porting as such and is symmetrical. All barrels even match grade ones have some degree of bend in them, and it's important to establish where this is, so optimal barrel alignment can be made to prevent crossover errors for POI at different ranges. Barrel bends are very easy to determine, and can even be quite accurately measured with the right equipment. Some barrels are more complex in that they have multiple bends, but I always arrange it so that the overall barrel bend has an upward orientation when located in the action. BSA barrels are the most linear of all the barrels I deal with. Walther are generally appalling with multiple bends, and I've had quite a few Steyr Anschutz/Walther barrels recently which have had marked bends as well as various anomalies with internal pellet fit. The stripper that I make is comprised of several components. The adapter which fits onto the barrel and has a half inch UNF male thread, a thread protector ring, the main airstripper body, and the cone insert which is usually made of stainless steel and brought to a high polish finish. The adapter on its own also functions as a means of attaching a sound moderator. I only make adapters and strippers in aluminium or mild steel now, not stainless, and the prices for this are as follows: UNF barrel adapter (if required) in aluminium XXXX, steel XXXX. Aluminium thread protector ring XXXX, steel XXXX. Stripper body in aluminium XXXX, steel XXXX. Polished Steel cones, with or without graduation XXXX. Handled Allen key and grub screw for cone fitment included. An alternative to the barrel adapter would be for me to thread your barrel muzzle directly with a half inch UNF male thread, and prices for this are XXXX for threading, and XXXX for crowning the muzzle with the polished 11 ° target crown. XXXX extra for a special custom thread protector ring. All plus return postage at cost. Let me know if you need any further detail. ATB, Drum."