Letter to Sig Sauer_from ullie

...FYI

...here is a copy of a letter i sent to Sig Sauer's product manager September 14 after i had a lengthly discussion with him September 11 on behalf of Ron Cohen...he was formerly an engineer for Sig Sauer and seemed to grasp the trunion issue as i described it...he requested my overall imput on the 556 in writing...presumably left open for further discussion...he led me to believe the trunion issue would be addressed starting the 14th of this month...there certainly can be no further denial of this issue since he...and presumably Ron Cohen are now aware of it...at his request i copied Ron Cohen...i spoke with Tabata Wade...Ron Cohen's assistant... yesterday and she assured me that they are taking this very seriously...

...ullie


Hello Eric;

Thank you for returning the call I had placed to Mr.Ron Cohen earlier in the week. As per our telephone conversation on September 11, I am putting some of my concerns and recomendations in written form as requested by you and will copy Mr. Ron Cohen as you suggested in this e-mail. Since we have already covered some of this verbably, i will keep it brief. As you already know I am retired and have been moderating a forum entitled SIGARMS556 in my free time: I am also familiar with and have experience with the 55x series of assualt rifles of which the 556 is clearly a member. I will provide links, so that you can have some feedback from your customer base...but primarily to provide you with photographs referencing the issues.

Item 1: I suspected, and you confirmed, that you are currently shipping the 556 with full auto bolt carriers. Although the BATFE does make exceptions to their general determinations regarding the use of full auto parts in Title 1 firearms; you may be in violation of the law. Sig Sauer certainly is not practicing due diligence or acting responsibly in the sense that with the availability of 55x compleat full auto lower recievers and associated parts; a 556 can easily be converted to a select fire weapon. There is absolutely no justifiable reason to ship the semi auto version with a full auto carrier. Although, for example, the BATFE has recently been allowing the use of full auto shrouded carriers in AR types; it would be flawed logic to assume that they will make this same determination with the 556. The BATFE makes these determations on a case by case bases and these determinations are weapon specific. I highly doubt that the BATFE would allow this knowing how easily a 556 could be converted. The legal consequences could be very severe and have serious ramifications in the firearms industry considering the current political climate, especially if a "converted" 556 were to be used in a violent crime.

Item 2: There is a machining error occuring in the trunion of recently produced 556s that allows the bolt carrier to impact the rear left side of the trunion on it's fowards stroke. It seems that the area next to the bolt caming ramp is not flush with the retangular portion of the rear of the trunion tail. The only area that the carrier "should" impact is the small raised triangliar area of the trunion located ~ 1 o'clock while looking through the ejection port. This will also leave a corresponding shadow on the carrier after the weapon has been fired several hundred rounds. The effects of this machining error are that the left upper corner of the carrier becomes scarred and that the weapon's accuracy may be affected...and there are others. Sig Sauer's solution was to "grind down" the carrier to fit or to tell customers that this was normal. It is not. The solution is to correct the CNC machining program and to releave this area on existing rifles as per our discussion.

Refer to link regarding this issue in following tread...the photos clearly show this.


http://www.sigarms556.com/viewtopic.php?t=6753


Item 3: The formation of an concave indentation on the hammer face caused by impacting the firing pin. The hammer face does not have sufficient "indendation hardness" as a result of the hardness and temper of the substrate material used. This is a quality control issue related to the blend of steel and method used to cast the hammer and is not a surface harding issue. This should not be occuring after only several hundred rounds.

Item 4: Due to an inadequate surface harding process or finish machining error, the hammer sear shelf is "rounding" on some of your weapons. The sear only contacts about half the width of the hammer sear shelf, so you can see a before and after on the hammer sear engagement. The rounding of the hammer ledge and to a lessor degree of rounding of the tip radious of the sear suggests that the metal is too soft on the surface in this area. Briefly...this could be a result of the limitations of the casting process used for the hammer...blend of steel...improper hardening...after hardening machining error..and such... The consequences could be an accidental discharge or the weapon firing more than one shot with a single pull of the trigger due to the sear being able to eventually slip out of engagement from the hammer shelf, or fail to engage. The weapon will also be more prone to accidental discharge when disturbed.

Some other suggestions
1. Use a mil-spec buffer tube, ie reciever extension. The important functional difference between a mil spec and commercial tube is that the treads on the mil-spec tube are cut to "full height"...aside from any demensional differences...the full height treads have a lessor tendency to loosen or "pull out" of the lower reciever. The plastic reciever extension makes the 556 look cheap; and perceptions of quality are everything to the consumer. BTW..you should not use a treadlocker, staking the castle nut is more than sufficient to keep the nut from backing off.

2. Install the crush washer properly. The larger diameter facing the flash suppressor: the small diameter thereof pressing against the barrel shoulder...and properly center it. I recomend using a peal washer instead to index the flash hider. The flash hider should be torqued to 20 foot punnds...without the use of a treadlocker.

3. Since the extractor spring is difficult to replace for most consumers, it should be made of HR CS wire which will give it a much longer service life.

4. In recomend using captivated push pins in the front and rear of the lower in all your models. You should use a single detent pin... don't double up two shorter detent pins per push pin.

5. Increase the top height of the bolt catch slightly to ensure capture of the BC group and increase the capture area somewhat to distribute the impacting loading over a greater surface area.

6. The compressive value of the firing pin spring needs to be increased so as to avoid a possible accidental discharge when using ammunition with the more soft commercial primers. The specs for the 55x series are based on the harder military primers.

7. The gas valve should be manufactured using something like inconal...an austenetic nickel-chrominum-molybdenum supper alloy...or an alloy of similar properties. This will significantly reduce the errosion of the ports in the valve and prevent cracking. As the holes enlarge in the thin skin of the valve walls from the blasting and gas cutting effects of the hot, high pressure gases mixed with the particulate matter of combustion...the resultant increase in gas volume will increase the recoil impluse which will increase the stress and resulting strain (fatigue) on the weapon as a whole and in particular the linier and rotational sear forces on the bolt lugs.

8. The recoil plate needs to be affixed to the reciever more evenly and securely.

9. The use of "coiled roll pins" (spring pins) should be utilized throughout the weapon, especially in high load areas such as in front of the washer support behind the recoil spring on the piston rod. The washer support should be "flat"...not rounded as shipped in some of your replacement parts kits.

10. Sig Sauer should consider shipping each Sig 556 with a "good" quality mil-spec NATO STANAG magazing...such as a D&H mag with a Magpul anti-tilt follower installed. The Sig magazine, i'm sure, is a source of grief for many...and also a possible cause for some of your returns. I will provide you an extensive account of the importance of a "good" magazine...and how critical they can be to ensure the functionality of any weapon. There really is more to a magazine than meets the eye.

11. There should be some changes made to your DMR; especially the length of the gas system and barrel twist.

12. On your new" patrol model"...I noticed Sig Sauer is using a "pistol length" gas system. Although "gas port" size can be played with, both in the barrel and "gas valve walls"...the significanty increased peak post pressure, gas velosity, gas density (due to the compressive nature of gases), and other such factors "mated with the carbine length barrel" will have adverse effects on the weapon far too numerous to point out in this short letter.

In all honesty Eric, unfortunately the image of quality that Sig Sauer once possesed is deteriating rapidly; especially the precieved quality of the Sig 556 series. Adding cheap, margionally functional accessories doesn't enhance your image in the market place and further detracts from your "branded" name; that has for years represented the pinnacle of firearm excellence. The information I provided above is only a small sampling. It is literally impossibly to cover, and go into any kind of meaningful detail within the limited scope of a e-mail or letter.

I encourage you or Mr Cohen to call me since I am more than willing to discuss these issues. I would also be willing to allow you to tape record the conservation for your convenience.

I will be sending you some photos...

Best Regards
Ullie