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Posted: 5/28/2007 11:28:37 AM EDT
| That bolt carrier that you call spare is for a sear blocked Colt. I don't know if it is in original configuration or been modified from a full auto. It should have a C stamped on the left front side of the carrier. Colt started leaving the firing pin shrouded around 2000 or later. The sear blocked guns are earlier but Colt kept the very PC half circle carrier as it is very hard to adapt to full auto fire. If there is no C on it it is converted from most likely a full auto bolt carrier. If #3 has the C stamped it is a Colt; the first three carriers look to be in Colt SP1 configuration. Most other semi bolts have a bit more full circle area than those??? It is not importat, just trying to help you identify your carriers. |
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Your Oly is properly identified. I concur that #4 is actually a Colt "half circle" carrier. The other three look pretty much the same except for finish and probably wear. Aside from the "all original" issue, why are you concerned about which BC goes with which rifle? It is the BOLT itself that is critical for headspace (and thus safety), not the BC. |
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I believe that the bolts are in the original carriers but it is possible that I mixed up a specific bolt/carrier combination from its origianal rifle at some point. By knowing which carriers go with which gun I can be more certain that the correct bolt is in the correct gun. As mentioned above there is no question about the Oly bolt carrier. Bolt carrier #4 did not come with the SP1 when I bought it in 1983. It appears to have never been used although the bolt that is in it has some brass residue. It is indeed marked with a C. Bolts 1-3 are all pretty much identical and therefore go to one of the 3 semi-auto guns. Bolt carrier #2 which is now in the the pre ban bushmaster is marked with a C so I am assuming that this belongs in the Colt SP1. The other semi-bolt carriers are unmarked which makes them Bushmasters. Is there any advantage/disadvantage to using the half circle colt bolt carrier so long as the correct bolt is used for a particular rifle. If anyone has anymore thoughts on this let me know. |
| Half circle carriers are a bit lighter, and of course they clear the idiotic receiver block Colt put in a lot of their lowers. I assume your Colt does NOT have such a block? (These things actually stick UP into the path of the bolt carrier, so only a "by God it'll NEVER go full auto" carrier can clear it.) |
| Yes the C marked semi-auto carrier would be proper in the SP1. The Colt half circle carrier is a good carrier (Colt quality) but it isn't anything special. I run all Colt M16 carriers because they have a little more weight and tend to cycle a bit better bewcause of it. The biggest bonus that half circle carrier has over the others is it's shrouded firing pin. It will be a smoother cocking with less wear and tear on the firing pin retaining pin than the exposed firing pin head carriers. The exposed firing pin carriers should have small head firing pins in them and the shrouded carriers can be either small or large with large being preferred - again due to being heavier for surer ignition. You really need to use the same bolt in the same gun as they wear together, switching them around too much will cause accelerated wear and tear on the bolt lugs shortening the useful life of the bolt. |
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