A while ago I bought a semi custom rifle in 17 Rem off this site that had been produced by a well known smith out of quality components. The deal was struck and the rifle delivered along with a set of dies, some once fired cases and some new brass. I was a very happy man... I started reloading for the new toy using established data and immediately noticed that on firing the primers were backing out of the cases a little. I assumed that this was down to me over sizing the cases and pushing the shoulder back, so I fireformed them again and adjusted the die with more care. All seemed well and the rifle would generally shoot very well, (particularly with Berger 25 grain bullets (21.5g N133) but suffered from regular, unexplained fliers which prompted further investigations. As the calibre was a lot smaller than I have loaded before I suspected my handloads and a concentricity gauge was sourced. This showed that my reloads for my other rifles were within 1 or 2 thou of being concentric but the rounds for the pipsqueak mousegun were a dismal 8-10 thou out of true, sometimes worse. Now suspecting the dies were rubbish I bought a Forster seating die and a Lee collet die in an attempt to control the run out. New cases were bought and the necks turned for 60-70% of their circumference. This improved the concentricity somewhat but was left with an annoying 4-6 thou of runout on the majority of seated bullets, with a bit less runout when measuring the case necks.... Oh well the rifle seems to shoot OK so I figured I would get on with fireforming the next batch of cases whilst shooting a few bunnies....thats when things started to get interesting as after a few rounds the firing pin jammed up and wouldn't set the round off. The shooting session was called to an end and the bolt stripped and cleaned, which resolved the issue. Out after dark with the rifle and shot a fox so was quite happy.
The following day I decided to check zero with the new batch of fireforming loads (25g bullet) and set a target up. The first three rounds seemed OK but then the fourth made an odd report. The case was sooted and there was a massive dent in the shoulder.....wierd! Checked the barrel and all was clear and there was a hole in the target suggesting the bullet had properly departed the rifle (it is a 17 after all!). The primer was a little flattened and there was an extractor mark visible, suggesting overpressure. I fired three further rounds that were loaded with 20g bullets that had been hanging around in the bullet box for a while and these seemed OK. Chalking the dented case down to a wet or oily case, I fired three more rounds of the 25g bullet fireforming loads before getting too worried and packing up. On firing the last round the plastic bolt shroud broke off and hit me in the face, all three had blown the primers out completely and had substantial deformation of the case heads. The shoulders of each case seemed rounded and misshapen compared to my other fired cases.
My local gunsmithing guru was consulted and after consideration of the history of problems with the rifle, it was suggested to check the headspace of the rifle by purchasing an appropriate gauge. A go gauge was ordered that mimics the minimum headspace of the 17 Remington and unsurprisingly this chambered without difficulty. The base of the go gauge was taped to increased the length incrementally (scotch tape has a thickness around 2 thou thick). To give you an idea of what is acceptable a 223 remington should have headspace tolerances within 2-4 thou, ie if you can still close the bolt after 2 layers of tape have been applied there may be a problem. I suspect mose cartridges will have similar tolerances. The go gauge was chambered and more tape applied providing the bolt handle would close readily. I became quite good at taping the base of the gauge as eventually I started to feel pressure on closing the bolt at go gauge +15 thou thickness and the bolt would not close on go gauge +17 thou. This means that the chamber appears to be substantially longer than it should have been, which explains the problems with excessive pressure signs, primers backing out and the unexplained fliers. It is even possible that virgin or full length sized cases were headspacing off the extractor claw at the moment of firing as they may not have been touching the chamber at the shoulder!! Neck sized cases would be less susceptible to showing these signs which may be why the problem had not been picked up by the previous owners. There is no sign of damage to the action lugs or bolt face and I can only assume that the rifle was not headspaced correctly when it was rebarreled. I cannot understand how the rifle ever passed proof!
At this moment in time the rifle is in dry dock... I am hoping that my local guru will be able to restore proper headspace by facing off the barrel at the breech and at the shoulder where the barrel tenon starts, before refitting the barrel. During this process I will hopefully find out if the chamber has been cut concentrically with the bore (which could explain the crooked case necks).
Why am I recounting this to you...well firstly most of us probably dont know how to check headspace or why it is important. I have learnt quite quickly because I suspect I was almost injured as a result of excessive headspace that is probably caused by faulty rebarreling work. Secondly when buying a semi custom rifle you are completely in the hands of the gunsmith who has performed the work. I have mistakenly fallen into the trap of thinking that the gunsmith performing custom work would be more diligent than a Remington employee churning out M700s every 10 seconds. This does not seem to be the case here! As in any walk of life, there are those who are diligent and meticulous and those who will cut corners. I am not going to name names as I don't feel that this is appropriate at this time, and I am neither upset or annoyed. I am however very glad that I have identified why I have experienced the problems with this rifle. However whenever I purchase a rifle in the future I will be checking the headspace measurements carefully before using the rifle.
Caveat Emptor indeed
PS I have just managed to download the saami spec for the 17 Remington and the min and max headspace measurements vary by 10 thou (as do many other cartridges) so my chamber is still waay too long!!