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Posted: 7/29/2008 2:19:28 PM EDT
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I believe I have bought an Olympic 22lr conversion kit. It came with 2 BDM Mags and is pretty reliable with Federal Bulk but not very accurate out of an older SP1 with 1 in 12" twist, maybe 3" groups at best at 25 yards. I seem to be getting alot of lead accumulating on the outside of the chamber insert. After 50 rounds when I remove the entire conversion unit, I notice a silvery coating on the outside if the chamber insert, which I believe is lead. It flakes off like lead. Is this normal? Should the chamber insert be sealing off the chamber better to prevent lead blow-back between the insert and the actual chamber? I would think I have an undersize insert or an oversize chamber, but whatever it is, I don't think this is normal. Any ideas? BTW, when shooting 55gr .223 South African military ammo, this rifle is a tack driver. |
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From my experience with a Kurt's Kustom Firearm 1 in 16 inch twist barrel I noticed significant change in accuracy when using a Ciener compared to a Colt conversion kit. I measured the depth of the chamber and the length of the chamber inserts. The Colt had a shorter chamber insert than the Ciener. I think the bullet had a longer jump from the end of the chamber insert before hitting the rifling with the Colt kit whereas the Ciener's chamber adapter actually touched the end of the chamber. Its possible the throat on your 1 in 12 barrel is a little deeper causing a pretty good jump for the bullet. You might measure your barrels and compare. On my 1 in 9 twist barrel the jump was shorter and didn't effect accuracy with the Colt kit compared to the Cieners. I also read where a poster put tape around the barrel/outside of the chamber insert to tighten the insert in the chamber to improve the accuracy. Another poster placed an O-ring around the barrel/outside of the chamber adapter to seal the chamber and keep the rifle cleaner. I hope this gives you a couple of ideas. Honestly I don't get very good accuracy out of Federal bulk packs. I can only get 2 to 3 inch groups out of my 1 in 9 twist barrels and 2 to 2.5 inch groups with 1 in 16 inch barrels at 50 yards. I get a lot better accuracy with Aguila 40 grain SE RN Plated and CCI Mini Mags. Before you assume its your barrel I'd try different ammo. Each barrel seems to prefer a couple of 22 loads. Changing ammo in a 22 lr can make a huge difference in functioning and accuracy. |
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