Hi all,

I have noticed that some PE-90’s and the earlier pre-ban semi-auto Sig 550’s have what appear to be proof marks on the right (ejection port) side of the gas block, while others do not. The marks appear to be a diamond with a number and/or other symbol stamped below it. As I mentioned, these marks are completely absent from the gas blocks of some examples, it seems particularly the case for the pre-ban imports (there are some posted on GunBroker right now that illustrate this).

I was wondering if anyone knew what these marks are/what their origin is? Are there differences in the desirability of PE-90s with marked vs. unmarked gas blocks? (Like there seem to be with many Colt rifles.)

Any info someone might have on this would be much appreciated.

Thanks a bunch!

My 2016 vintage Pe90 does have markings on the right side(ejection port side) of the gas block. My only guess is that these are military parts and possibly the 550s were purely civilian and used unmarked parts.  I doubt that the presence or lack of such marks in itself would affect the value or desireability much.

That would make sense. I’ve seen PE-90s without the marks, too, and even the marks themselves differ from rifle to rifle. I wonder if they’re just getting the parts from different sources, e.g. military contract overruns, dedicated civilian parts, etc.

I just went back through a ton of saved screenshots. I know I have seen an explanation of all those proof marks but for the life of me I can’t find it.

I appreciate all that effort! I’ve definitely tried to dig on this topic but still can’t find rhyme or reason to it, although of course I know there is. If you do find anything, I’d love to know.

Tagged because I am curious to learn. Calling JoshNC and others......

I have a JDI PE90, so I don't count in this conversation

Thanks I appreciate it!

Lol, if I may ask, how come JDI imports don’t count?

Because they are imported as “PE90P” or 550P for pistol markings with JDI’s stuff. The PE90 original Swiss markings are considered more desirable.

I just want to shoot mine and keep it, so I don’t care.

That depends on who you talk to... generally yes the JDI billboard is less attractive, but both sets of guns have some other minor differences that some may find preferable over the other.

I’ll look at my 55x rifles and spare gasblocks. I’ve never thought of anything being more collectible due to the casting codes in the gasblock, moreso when the rifle was manufactured, how it’s marked, in what configuration it was imported (rifle vs pistol), and who imported it.

Legit pre-89 rifles (not recent imports masquerading as such) are the top of the heap. These were 550-1, 550-2, and 551-2. There are also a few PE90s.

Post-89 LE imports without import markings are very collectible, followed by post-89 LE imports with import markings. These include PE90s, 550s, 551s, and 552s.

Post-89 commercial pistol imports by M+M, JDI and a handful of others make for nice shooters, but don’t command collector premium the others do at the moment. I personally feel the SigSauer USA imported 553s are the most collectible of all the 553s.  The models that weren’t available pre-89, like the 751 and 553 are collectible regardless of who imported. And in time the importer will be less important with exception of advanced collectors who know the differences.

The prebans lack features such as the bayonet lug and grenade ring. They command the highest price on the virtue of being "preban," but I have seen many collectors prefer the pistol imports on the basis of the missing features.

Furthermore something like the 553s, again it depends - the Sig USA 553's only came in one configuration I'm aware of (black diopter/alloy lower), for someone who wants something else, the importer is less important than the configuration.

Exeter imports had railed and diopter receivers. All had aluminum Swiss mag lowers. All black.

Collecting is all about preferences and is totally subjective. The pistol imports have their own unique challenges unless one submitted a free form1 during the brace amnesty. Unless we see legislative change, I believe true rifle imports will always command a higher premium than pistol imports, even with neutered features.

Again all subjective, but in my opinion the current imports are neutered in the billboard import markings on the receivers, lesser quality of current ilaflon paint compared to legacy, the addition of P to all model markings, satin sheen of the nitride on some barrels, the date stamp on uppers and lowers, the dimpled dust cover rivets, and the black color of the trigger, selector axle, and selector levers. The older guns are much nicer in my opinion. Of the pistol imports, I prefer the legacy guns that have more discrete import markings on the barrel. But again, these are just my opinions, not gospel.

We may see all of them jump in price soon with ATF cracking down on all large pistol imports:

https://comms.wiley.law/8/3583/october-2020/alert--atf-interpretive-change-restricts-handgun-imports-and-may-require-nfa-registration

Back to the topic of markings on gasblocks.

I have had half a dozen or so of the 1980s manufactured recent pe90 pistol imports in my hands, all of which had the casting codes on the right side.

Of the other SIG 55x that are either mine or belong to friends and I’ve had in my hands:

Early 80s pre-89 import 551-2 with the very early green matte colored gasblock, no bayonet support boss, and it lacks any markings. I have a spare gasblock that I bought from a seller in Germany around 20 years ago and it’s identical.

Post-94 pre 2004 LE import (directly imported from Switzerland by the LE agency) 16” oal barrel 551-2. Lacks the bayonet lug support boss. Semi gloss gray ilaflon paint with casting codes on the right.

Late 90s early 2000s era 551-2 14.3” barrel  post sample MG imported by Sigarms. Semi gloss gray ilaflon paint with casting codes on the right.

Three or four 551-1 LB barrels from CCF kits. Not sure when they were made, but were imported by CCF from Canada in the late 90s. Semi gloss gray ilaflon paint with casting codes on the right.

Two 552-2 barrels from CCF kits. Not sure when they were made, but were imported by CCF from Canada in the late 90s or early 2000s. Semi gloss gray ilaflon paint with casting codes on the right.

Two 552-2 SBRs Sigarms imported in the late 90s early 2000s for LE. Semi gloss black ilaflon paint with casting codes on the right.

Three 551-2 SBRs Sigarms imported in the early 2000s for LE. Semi gloss gray ilaflon paint with casting codes on the right.

Two M+M import 553 pistol. 2012 manufacture. Duller black ilaflon paint with casting codes on the right.

Two SigSauer import 553 pistol. 2014 manufacture. Duller black ilaflon paint with casting codes on the right.

Pre-89 550-1 Sigarms Herndon VA import. Semigloss darker gray green ilaflon paint, no bayonet support boss, and it lacks any markings.

The earliest Sig 556 used Swiss gasblocks that were finished in the US and had casting codes on the right.

JoshNC, Apec, themao,

Thank you, that was a lot of great information. I’m fairly new to 550s/PE-90s and don’t know a lot about the intricacies of the different iterations/versions through time, so that was a nice crash course.

It’s interesting what you mentioned about the satin finish on some of the PE-90 barrels. So some do indeed have a glossier finish on the barrel? I thought I noticed that from pictures, but also thought it could just be oil. (Besides pictures, I am working with a sample size of one, which has a matte finish.) Is one finish of higher quality/durability than the other?

I’ve also seen people mention different barrel manufacturers. I think CO Gunsales has one posted on GB right now with what they claim is a Hammereli (I may be misspelling that) barrel. Are there noticeable differences in the barrel quality of different imports/contractors through time?

That’s also interesting what you mentioned about the finish being of lower quality on the newer imports compared to the older versions. Not to go on a tangent, but I have wondered this about HK91s and the “HK gray” finish bs the “NATO black” finish on the models imported in the late 80’s.

Thanks again!

JoshNC,

Wow, thank you for that. I imagine it probably took some time and effort to go back through all those, and it’s much appreciated!

That’s really interesting, so it sounds like the only 550 that didn’t have the casting codes is a pre-89 import.

The sample size of I mentioned in my post above, is a fairly recent JDI import, no casting codes on the gas block.

Given that Swiss stocks in the last 1-2 years no longer have a manufacturer embossed at the front, I bet SAN has changed up the gasblock too. They likely had a bunch of NOS parts and are now using newer manufactured items. Just spitballing here….

That article is outdated - note the 2020 publication date. It was relevant when the ATF was working on the brace rule and the infamous points chart, which would have had an impact on imports then. Even Dave Wagner was preaching it, to the point he imported unfinished guns in a desperate effort to beat the ban that never came… but years passed and he’s only brought in more guns than ever since.

The chart was scrapped to my knowledge, and the brace rule has been stayed. I have talked to importers of non-JDI PE90s, as well as Dave, and none have indicated any issues with pending or future imports.

There has been some hearsay floating around about certain pistol imports getting denied before/around SHOT 24, but I have seen little in the way of concrete evidence or details indicating a systematic effort by ATF to do so. If anything there may be some isolated events that are not indicative of a general correlation.

Thanks again JoshNC for chiming in. Great info. We need to link this thread to a Sig 55x chain of threads.

The article is discussing pistol imports, not braces. I don’t see a 2020 publication date either. ATF has had a hard on to stop the import of pistols with OAL greater than 26”, which used to be the litmus test.  From what I’ve heard, the new spurious decision to limit some pistol imports is anything but hearsay. Whether they actually do it remains to be seen.

I own one of the rushed JDI import 551 without ilaflon paint on the upper. It’s a brace amnesty registered SBR, so it’s going to need some paint at some point.

The reason I mention the brace panic is because the ATF brace worksheet (which appeared in late 2020) had checklist items that would classify a pistol as a SBR regardless of a brace being attached or not. These items include overall weight, "rifle" sights, ability to accept a stock and ammunition type. NFA items cannot be imported, so if it had played out as the ATF intended, that would absolutely have stopped most imports.

Needless to say the worksheet fizzled out and is even more irrelevant from the recent stay in federal court.

I say the recent revival of this talk is hearsay because I have seen zero detail beyond people saying "a reputable source told me so." Zero names of importers involved, zero mention/detail of the products that got denied.

Following my inquiries with a few other importers on future product availability, to include Dave Wagner himself, I was not informed of anything involving ATF disapprovals across the board - which led me to further doubt the credibility of the import ban claims.

The article you posted is this one, just that the version you linked to is formatted so the pub date isn't shown - note the October 2020 date: https://www.wiley.law/alert-ATF-Interpretive-Change-Restricts-Handgun-Imports-and-May-Require-NFA-Registration



Now it may be possible the ATF is actually doing something, but I think the evidence is extremely thin and not conclusive enough to support that. As I suggested earlier, the ATF has always arbitrarily denied import of some models (IE the JDI Sig 750 in 6.5CM), and a handful of disapprovals don't necessarily constitute widespread action.

Anybody seen anything newer than 2023 imports for any large format "pistol'?  Rumor is any barrel length over 11" won't be approved...heard from several folks I know who were at SHOT in January.  No source to quote, however.  

That’s the problem I’m referring to. The source is conveniently anonymous, in other words, unvetted. Back in 2020, the brace worksheet was actually leaked when all of this was going down, so it was more credible back then. The lack of industry reaction to this alleged upcoming ban also casts skepticism, given how many importers, manufacturers and products this would impact.

A few months back we got a few industry people pushing an unfounded rumor that gas blocks and front trunnions would not be allowed in imported demilled parts kits. Turns out this was all the result of a misunderstanding of ATF destruction diagrams. In the absence of more credible information, I am inclined to believe something similar has occurred here.

Alas, it came from two different industry sources both coming back from SHOT.  It's all RUMINT until we see something concrete or 2024 stamped imports make their way in.  The only thing concrete so far is no more approved H&K MR223 imports which tracks perfectly with this SIG related potential prohibition.

The main issue is not the new production Swiss "pistols" but rather the difficulty in monitoring the gray market importers buying up new or used "rifles" in the EU, taking stocks off and using JDI's hard-earned import approvals in the eFile system to get non-JDI items approved for import.  That's what BATFE is trying to shut down, it appears

Maybe these: https://swissarmsusa.com/product/551p-lb-welded-diopter-pic-rail-deposit/


JDI has these up on their/his webpage. I don’t think they’ve have actually made in the country yet, but I presume people have been placing orders, as I saw change from “available” to “out of stock,” as I checked the website over time.

Agreed.

Prior to B&T USA getting approval to import 16” barreled apc223 pistols, ATF summarily rejected pistol imports with OAL greater than 27”. Maybe they are going back to that, maybe they are not.

I sincerely hope not. It will be great if we actually see Pindad FNCs imported.

Frankly, it would be great if someone simply sued ATF re: importing full feature rifles given the 2a court victories. It’s a perfect time to go after the sporting purposes clause of the 68 GCA. It is contradictory to the intent of the 2a. Seems like a chip shot with current case law from Bruen, McDonald, and Heller.

Thanks, I missed the 2020 publish date.

I agree. And yes, the disapproval of the 6.5cm 750 had me thinking ATF was going to crack down across the board.

We shall see. As I mentioned above, it’s a great time to take the 68 GCA to court.

And also the 1989 import ban which seems to be done by EO.

Absolutely. The power to enact that ban comes from sporting clause of the 68 GCA.

Sample of one, a 4 digit PE90 imported by M+M that I recently received - for the purposes of the original thread this has a proofed gas block, as does the 551 I am comparing to. Couldn't exactly compare it to a JDI 550 since I traded that gun, but a 551 is close enough.

What do you consider the cutoff date for a legacy vs current production gun?

Beautiful rifles! Love the PE90. Import marks aft of the gasblock on the bottom of the barrel?

Tough black and white distinction between legacy and current production. My best guesstimate is mid 2000s when the paint changed. I recall a conversation that Ilaflon changed to adhere to updated environmental regs in Switzerland, but I don’t remember when that was.  I think it was David Hume who told me that. I’ll hit him up and see if he remembers.

Gray definitely changed in color and texture. Black changed in texture.

The black oxide trigger, selector axle, selector levers, dimpled dust cover rivets were seen in the last 3-5 years iirc.

I thought I remember Ed reading on JDIs Facebook that those black parts were part of a nitride corrosion resistance upgrade.

Import mark is under the barrel indeed.

“Upgrade” 😂

That’s a truly gorgeous PE90. Congratulations.

https://i.imgur.com/m5CvoIA.jpeg

https://imgur.com/a/tkVJ7CF


So yes upgrade.  More pics on Jdi facebook page

I still don’t like it on legacy models. It’s like upgrading a Colt SP1 with an LMT e-carrier, nitrided ambi selectors, and an ambi mag release.

Very true.

Unfortunately many a SP1 has been massacred by someone in a ban state trying to trick out a preban lower.

This +1

Humbly, great info gathering.    Here is my take as a Forrect Gump along for the ride since the mid 80's.
My 551-2 police RIFLES x3 are all Hammerli.   I have others I would need to check.   All barrels are made by SIG then sent for finishing at different sites. One being Hammerli. Your barrel number will tell you who and if there was additional QC and if SIG proper finished it. There is a chart out there.  Also there is a/or an additional testing procedure that can happen .  It is based on the test fire and more test fire ratio info.

I believe that a Hammerli finished barrel ,  although considered "meh" by some due to sheer awesomeness of the barrels in general , is indeed a bonus especially 20 years from now



I'm I wrong?  I can change or delete my post quickly.    
fwiw

To which auction are you referring? The CCF marked 551 you posted in another thread?

Correct, I was on a rant and got my threads mixed up.  I removed that part of my post. Thanks !