Modern Sporter builds Q&A

[no-one special]

Two different guys having the same issue... Odds are it's not the cover. I looked online to see if anyone else is having this issue and couldn't find anything. I wonder if there's a slight difference between the area around the ejection port on the MS and a typical AR.

In any event, yeah, running a bead of epoxy along the contact point of the cover should do the trick. Another option is to shave a very slight amount
from the tip of the plunger that keeps the cover closed. Maybe even cycling it a few dozen times would help. I know from experience that worn covers tend to spring open with just the jolt of the action being racked. I had one like that in basic and got jacked for it every day because it was always open :D

Edit: I haven't got my MS yet but my lightweight carrier *should* be arriving today if my Postie isn't too traumatized by the snow. I'll try it in my MDI and see if it works.

Yes the ejection port IS different between a Sporter and an AR, the Sporter is bigger so as to better accomodate big bore cartridge, this was discussed a fair bit back when the uppers were still in the infancy stages.
Some of the light weight carriers have the sides of the carrier scalloped out to remove weight. If the carrier can't contact the port door due to material missing the door then has to wait for the bolt head end which has not been altered to do the job.

[Holycow]

I've never built an AR before so this might be an obvious question but:
Do you guys have any recommendations for lubrication?
I understand you're supposed to apply some grease to the barrel nut threads?

[yowski]

I've never built an AR before so this might be an obvious question but:
Do you guys have any recommendations for lubrication?
I understand you're supposed to apply some grease to the barrel nut threads?

I use AeroShell 64 for the barrel nut.

[Kratos]

Anyone try a 22lr kit yet? My bolt doesn’t work, looks like the upper is shorter then an AR15 upper by .175 thou, the end of the BCG sticks out and there’s a tab at the back up top to retain the BCG return spring.







The pictures show the tab and why it won’t work how it’s currently set up. The only part I can see modifying is the area the BCG locks into the barrel, skim that down on a lathe .175” and the whole carrier moves into the upper. Might have to get a different setup if this doesn’t work.

Or cut a notch in my lower where the tab would go... :D

[scourge18a]

You have to slide the upper rearward into the buffer to get the front pin to latch.

[greg olmstead]

Anyone try a 22lr kit yet? My bolt doesn’t work, looks like the upper is shorter then an AR15 upper by .175 thou, the end of the BCG sticks out and there’s a tab at the back up top to retain the BCG return spring.







The pictures show the tab and why it won’t work how it’s currently set up. The only part I can see modifying is the area the BCG locks into the barrel, skim that down on a lathe .175” and the whole carrier moves into the upper. Might have to get a different setup if this doesn’t work.

Or cut a notch in my lower where the tab would go... :D

That's one of the ways they got it nr was shortening the upper and making the back of the lower thicker. My bcg sticks out of the upper the same amount

[QuickDraw16]

Anyone try a 22lr kit yet? My bolt doesn’t work, looks like the upper is shorter then an AR15 upper by .175 thou, the end of the BCG sticks out and there’s a tab at the back up top to retain the BCG return spring.







The pictures show the tab and why it won’t work how it’s currently set up. The only part I can see modifying is the area the BCG locks into the barrel, skim that down on a lathe .175” and the whole carrier moves into the upper. Might have to get a different setup if this doesn’t work.

Or cut a notch in my lower where the tab would go... :D

My BCG sits proud of the upper even when it is at its farthest point in travel.
I thought that it was a little unusual but if you push the upper backwards the carrier engages the buffer and closes the gap.
It seems like that’s how it was designed to work.

Unless the tab at the rear end of the BCG is too tall to fit inside the buffer tube... it’s hard to tell from the pictures.

[Kratos]

My BCG sits proud of the upper even when it is at its farthest point in travel.
I thought that it was a little unusual but if you push the upper backwards the carrier engages the buffer and closes the gap.
It seems like that’s how it was designed to work.

Unless the tab at the rear end of the BCG is too tall to fit inside the buffer tube... it’s hard to tell from the pictures.

Sorry, the tab is too tall, it won’t slide back as it does with regular BCG’s.

You have to slide the upper rearward into the buffer to get the front pin to latch.

Lol I tried pushing back pretty hard before realizing the tab was stopping me.

[ATRS Shaun]

Sorry, the tab is too tall, it won’t slide back as it does with regular BCG’s.



Lol I tried pushing back pretty hard before realizing the tab was stopping me.

Well that's just frustrating... Which brand of 22 kit is this?

Gonna have to take a look at what we can do to get this working.

[Kratos]

Well that's just frustrating... Which brand of 22 kit is this?

Gonna have to take a look at what we can do to get this working.

It’s a Spikes Tactical Kit, I gutted an upper. I have a lower in run 2, if you can cut a notch over the buffer tube loop I’m happy with that (if there’s an extra cost for machining I’d also understand). The charging handle would cover the notch anyways. The more I look at it the more I think the barrel needs that material, it’s right where the chamber ends.