citizensoldier16
04-05-09, 16:34
I recently sent Bushmaster (groan already...) an email complaining about the quality of their rifles. More specifically, I complained that they do not use "F" marked FSBs on their flat-top rifles. The piece I would need to correct this, other than a correct FSB, was a taller front sight post. A $5 part from BM, and not a big deal. However to me, it was the effort at proving a point and maybe, affecting how they assemble their rifles. Anyhow, I complained via email. A portion of that email is posted below:
"I noticed that the FSB (front sight base) is not marked "F". A FSB that is marked "F" would indicate that it is suitable for use with a flat top upper receiver. Mine is not, nor are the FSBs on other Bushmaster rifles manufactured as A3 style rifles that I have inspected.
The problem I am having is that I cannot zero my back-up iron sights. The front sight post is almost all the way out and the rifle still shoots high at 50 yards. The correct FSB for any flat top receiver would be one that is 1.98" as measured from the top of the barrel to the bottom of the sight indentation. The FSB that came on my rifle measures 1.94" as measured the same way. FSBs that measure 1.94" are intended for use with A2 receivers, not the A3 style according to military specifications.
Is this standard practice during the production of Bushmaster firearms - mismatching the FSB with the upper receiver used in production, or strictly using standard FSBs regardless of the application?"
To which I quickly got two replies within 24 hours:
"We use the same from sight base on all rifles, if you are using a ARMS 40 REAR SIGHT then you will need the taller from sight post because they are not in the same sight plane. If you send me your complete name and address along with the serial number I can put one in the mail for you.
Thank You....
Harvey Macomber
Customer Service / Sales
Bushmaster Firearms International, LLC
Office: 1-800-883-6229 ext.286
Fax: 207-892-8068"
And...
"When Colt came out with the A3 design with the detachable carry handle they made the front and rear sights .040" higher than the sights used on A1 and A2 rifles. The front sight forging is the same but the front sight post when set for mechanical zero is even with the top of the sight ears instead of below them as the plane for the sight post is milled higher. You will notice on 20" A3 barrels there are two raised bands on the barrel under the handguards. This designates that the barrel has the front sight base with the front sight that is milled high for the front sight post. Colt parts lists have a different part number for the higher front sight base barrels and sight bases for A3 and M4 barrels.
Bushmaster decided when we began to build the A3 models with detachable carry handles that we would keep the sight heights the same for all models. Our A3 handle, BMAS Flat-top Rear Sight and BMAS Rear Flip Up Sight has the same rear sight aperture height as on the A1 and A2 receivers so that all barrels with standard height front sight bases will interchange. The Mark Brown Flat Top Mount also uses this same rear sight height.
The A.R.M.S. Swan Sleeve, # 40 Flip Up Rear Sights, Colt A3 handle and G.G. & G. have the higher rear sight aperture height. When used with standard height front sight bases the front sight post must be turned out to the .040" higher position where it is even with the top of the sight base ears for mechanical zero.
We now carry a .040" taller front sight post, part number 9349056-M for $5.50. But since your rifle will not zero, we'll be happy to send you one free of charge."
I received the taller sight post in the mail, along with a current catalog, in 3 days. It's a seemingly insignificant part when I think about all the high-dollar aftermarket parts I've put into this gun to make it better, but its all about principle and good customer service to me.
"I noticed that the FSB (front sight base) is not marked "F". A FSB that is marked "F" would indicate that it is suitable for use with a flat top upper receiver. Mine is not, nor are the FSBs on other Bushmaster rifles manufactured as A3 style rifles that I have inspected.
The problem I am having is that I cannot zero my back-up iron sights. The front sight post is almost all the way out and the rifle still shoots high at 50 yards. The correct FSB for any flat top receiver would be one that is 1.98" as measured from the top of the barrel to the bottom of the sight indentation. The FSB that came on my rifle measures 1.94" as measured the same way. FSBs that measure 1.94" are intended for use with A2 receivers, not the A3 style according to military specifications.
Is this standard practice during the production of Bushmaster firearms - mismatching the FSB with the upper receiver used in production, or strictly using standard FSBs regardless of the application?"
To which I quickly got two replies within 24 hours:
"We use the same from sight base on all rifles, if you are using a ARMS 40 REAR SIGHT then you will need the taller from sight post because they are not in the same sight plane. If you send me your complete name and address along with the serial number I can put one in the mail for you.
Thank You....
Harvey Macomber
Customer Service / Sales
Bushmaster Firearms International, LLC
Office: 1-800-883-6229 ext.286
Fax: 207-892-8068"
And...
"When Colt came out with the A3 design with the detachable carry handle they made the front and rear sights .040" higher than the sights used on A1 and A2 rifles. The front sight forging is the same but the front sight post when set for mechanical zero is even with the top of the sight ears instead of below them as the plane for the sight post is milled higher. You will notice on 20" A3 barrels there are two raised bands on the barrel under the handguards. This designates that the barrel has the front sight base with the front sight that is milled high for the front sight post. Colt parts lists have a different part number for the higher front sight base barrels and sight bases for A3 and M4 barrels.
Bushmaster decided when we began to build the A3 models with detachable carry handles that we would keep the sight heights the same for all models. Our A3 handle, BMAS Flat-top Rear Sight and BMAS Rear Flip Up Sight has the same rear sight aperture height as on the A1 and A2 receivers so that all barrels with standard height front sight bases will interchange. The Mark Brown Flat Top Mount also uses this same rear sight height.
The A.R.M.S. Swan Sleeve, # 40 Flip Up Rear Sights, Colt A3 handle and G.G. & G. have the higher rear sight aperture height. When used with standard height front sight bases the front sight post must be turned out to the .040" higher position where it is even with the top of the sight base ears for mechanical zero.
We now carry a .040" taller front sight post, part number 9349056-M for $5.50. But since your rifle will not zero, we'll be happy to send you one free of charge."
I received the taller sight post in the mail, along with a current catalog, in 3 days. It's a seemingly insignificant part when I think about all the high-dollar aftermarket parts I've put into this gun to make it better, but its all about principle and good customer service to me.