We have experienced continuing problems with the Hammerli SP20 .32 S&W when using 98grain head Lapua ammunition. The ammunition is used as it is very accurate, reliable and available, albeit costly. Unfortunately, a high number of recoil buffers are being broken. Considerable care is taken to measure the end of frame to buffer but after 500 to 2500 rounder, the screw retained the buffer breaks. Whilst the screw is low cost, the screw thread breaks inside the recoil buffer, requiring the complete replacement of the buffer and screw. Any information on how this can be prevented whilst still using Lapua ammunition use would be appreciated.
paul-at-lans.demon.co.uk.44149.0
Hammerli SP20 .32 recoil buffers
Moderators: rexifelis, pilkguns
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Paul R, Canada
Re: Hammerli SP20 .32 recoil buffers
I am told that the lapua ammo is a bit hot, equal to about 1.6 grains of Bullseye.
Where is your buffer set. The manual says tighten it, and then back off 2.5 turns. I go 3.5 turns with factory ammo. I'm still playing with the buffer adjustment to see what the difference is.
My suggestion would be to try a heavier grease on the rubber half o-ring, making a better seal and thus using air pressure to help slow the recoil. I use vacuum grease which is quite viscous and stays that way even at high temperature. An interesting engineering note is that in the .22 they call for an oiled slide, and the .32 they ask for grease. I don't know of anyone breaking the screw on the .22.
Question for you on another topic. I am having extraction problems with mine. Does your extractor hold the fired brass tight to the breech face? I think my extractor (or breech face) is a bit out of tolerance, causing my extraction problems.
paul.ruppert-at-utoronto.ca.44171.44149
Where is your buffer set. The manual says tighten it, and then back off 2.5 turns. I go 3.5 turns with factory ammo. I'm still playing with the buffer adjustment to see what the difference is.
My suggestion would be to try a heavier grease on the rubber half o-ring, making a better seal and thus using air pressure to help slow the recoil. I use vacuum grease which is quite viscous and stays that way even at high temperature. An interesting engineering note is that in the .22 they call for an oiled slide, and the .32 they ask for grease. I don't know of anyone breaking the screw on the .22.
Question for you on another topic. I am having extraction problems with mine. Does your extractor hold the fired brass tight to the breech face? I think my extractor (or breech face) is a bit out of tolerance, causing my extraction problems.
paul.ruppert-at-utoronto.ca.44171.44149