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Posted: 12/16/2016 7:49:21 PM EDT
| I'm new here and there is so much great information! Thanks! I'm sure my question has been asked many times, but still looking for an answer. When building from an 80 % lower, does it matter or not matter if it says multi cal? in other words, can I put any upper that is built for an ar15 on any milled out 80 % lower whether it says multi cal or not? What about magazine sizes? I've read you can put a 17HMR on an ar15. How would the magazine work in that case? Thanks |
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Unless some state law in your state says otherwise, you don't have to put anything at all on a lower you build yourself for personal use.
Markings don't prevent you from using other calibers, as long as they'll physically fit inside a magazine you can put into the magazine well. 17hmr would require a special magazine. Alexander Arms makes them, probably others. |
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caliber markings not an issue. Suggest you save a lot of time and effort and buy a PSA complete lower for $139---$169---$189. says blemished....I have several....no blemishes....just cheaper price. Check daily specials BTW......delete the duplicate you posted +1. I have built two 80% lowers. I also have high quality lowers I purchased. There is a lot of labor involved in milling an 80% lower, along with the cost of the router jig and router, if you do not have one already, plus the cost of disposable supplies such as the end mill. See post I quoted^. |
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+1. I have built two 80% lowers. I also have high quality lowers I purchased. There is a lot of labor involved in milling an 80% lower, along with the cost of the router jig and router, if you do not have one already, plus the cost of disposable supplies such as the end mill. See post I quoted^. Labor intensive? I don't think so, not if you buy the correct tools to do the job. |
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So is there any physical difference between an 80 % lower marked multi cal and an 80 % not marked with that? Of course there is. One has been engraved with "multi cal" and the other has not. Most "80%" lowers are not engraved at all - if you want words and stuff on them, you'll have to put them there. |
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Here are a few tips from my experience:
- Check your chosen supplier's product carefully. I have seen an 80% lower that did not have Safe/Fire markings. - 6061 aluminum alloy is a lot easier to mill than 7076. Check out this link: http://www.80percentarms.com/pages/6061-t6-vs-7075-t6-billet-lower. So far we like our 6061 lowers and still have a 7076 waiting to be completed as it is more time consuming. BTW this one does not have Safe/Fire markings. I do not recall the OEM of it. - Myself and others I know have had excellent luck with 80percentarms.com lowers and router jig kits and parts. Excellent service and parts. We also like their enlarged trigger guard that is forged as part of the lower. - Assuming you use a router jig kit, go slowly and do not take too deep of a bite with each pass. Make sure you lube/oil the end mill shaft so galling of the template does not happen. - We bolt the jig kit together around the receiver, secure in a vise like this and then clamp the vise assembly to a table or drill press as appropriate. Very stable and easy to work with. https://www.amazon.com/DELTA-20-619-6-Inch-Drill-Press/dp/B00004Y9F2/ref=sr_1_15?ie=UTF8&qid=1481975419&sr=8-15&keywords=6: vise&tag=vglnk-c102-20 - I have not had very good luck with a PSA lower receiver parts kit (others on AR15.com have a different experience) and I have standardized on CMMG kits. Lots of good parts out there. |
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...Check your chosen supplier's product carefully. I have seen an 80% lower that did not have Safe/Fire markings. Which is not necessarily a bad thing. What if you wished to use something other than the plain old everyday safe/fire script? What if you wanted to use the pictogram or other custom markings?What if you plan on using one of the newer style 60º safeties that are starting to become popular? Myself, I like clean and simple. I just spot drill the two locations and fill the divot with a drop of model paint. 
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- I have not had very good luck with a PSA lower receiver parts kit (others on AR15.com have a different experience) and I have standardized on CMMG kits. Lots of good parts out there. What problems did you have with PSA LPK's? I've used 5 without any issues. |
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One of the take down pins diameter was a bit larger than it should have been and would not operate correctly. Filing around the pin's diameter did not help much as it must be hardened. And the bolt catch had additional material in a slightly raised fashion on one side and would not install into its slot, even with filing for 30 min. on this hardened part. I could not tell the exact problem until the catch was held at an angle and then the problem became clear to the eye but could not be felt with the fingers, as it was smooth and raised. Kinda like it was a little pregnant. Fortunately I keep enough spare parts to build another firearm if necessary and replaced with CMMG units, which I typically use anyway.
I was building a "truck gun" with an 80% lower and also had trouble with a PSA 10.5", 1:7 barrel. At 36 yards zeroing with a Meprolight Tru Dot red dot (also my standard) the groups were more like a shotgun pattern using AE XM855 and IMI 855 (my standard testing and zeroing ammunition). I purchased this barrel for ~ $80 plus shipping when on sale so was not expecting much and was more of a cost experiment for future purchases, than anything else. Plus I did not need tack driving accuracy for its intended purpose. I replaced this with a Green Mountain 10.5" chrome lined 1:7 for ~ $160 and the groups were as good as my BCM cold hammer forged 16" barrel. Both like 55 grain - 77 grain and shoot to the approximate same POA. |
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I will have to give a +1 to 80percentarms. Ordered an 80% and jig Friday, received it here in SC from CA today. Outstanding. Will start a thread when I get started with my build.
Will probably try a PSA build next time since I live about 5 miles from their store. |
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Quoted:
I will have to give a +1 to 80percentarms. Ordered an 80% and jig Friday, received it here in SC from CA today. Outstanding. Will start a thread when I get started with my build. Will probably try a PSA build next time since I live about 5 miles from their store. |
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