GENERAL

I managed to find some documentation that listed US manufacturers of ammunition in which it states the 'A' marking was the code for Apex Metal Stamping Co. also 'G.G.G.' and 'G.G.M.' are codes for G. G. Greene Metal Stamping Co and 'B G R' is the code for Associated Spring Corp BGR Div. Recent aquasitions and research have forced me to relook at 100's of US made stripper clips searching for minor manufacturing details. Because the US didn't put date markings on their clips, it seems like some manufacturers altered their markings to indicate different production runs. This is evedent when you look at Seymour 'SEY' manufactured clips, to date I have managed to find at least 6 variations of their 'SEY' stamping. Also the design of the spring has been changed at least three times altering the end profile. From an email from 'Bert' "Just took a look at your stripper clip listing and noticed that in the US section you identify "Lufkin" as being Lufkin Industries in Lufkin, TX. That is incorrect. The Lufkin Tool Company was originally located in Michigan and ceased operations in 1967. It was noted for its line of flexible metal measuring tapes, though it made a variety of other tools." Webpage updated. From Douglas K Wozny :- These clips are known as Clips, Cartridge, 7.62MM, 5-Round and are covered by military specification MIL-C-45404 and drawing B7790130.
Version A Stripper Clip I believe this to be the first version of American clip as it closly resembles the Canadian Charger (stripper clip) in the way the spring is manufactured and it's known the Canadian's had a close working relatioinship with the US when dealing with Ammunition standards. The end of the spring looks like this:- I have classified this version of spring as Rounded Corners.
Version B Stripper Clip Not sure if this is just a production variation from Seymour, but the corners have a slight rounding. The end of the spring looks like this:- I have classified this version of spring as Rounded 45 deg Corners.
Version C Stripper Clip This version of clip has a hole in the spring, I have seen examples with the rounded 45 deg and sharp 45 deg coners. Probably an early version of clip for some reason it has a hole in the centre of the spring like early versions of the M1903 Springfield clips. I have classified this version of spring as Hole Type.
Version D Stripper Clip By far the most common version of clip, the sharp 45 deg corners were probably done to speed up production. The end of the spring looks like this I have classified this version of spring as Sharp 45 deg Corners.

DETAILS

Version A Stripper Clips
Ser	Marking	No of Stops	End Profile	Stop Posn	Material	Finish	Colour	Manufacturer	Notes
1	A	1	3	Top	Steel	Phosphated	Med Gray	Apex Metal Stamping Co. Brooklyn, NY ?	Large 'A' 3.96mm (5/32 in.) wide 5.55mm (7/32 in.) high.
2	A	1	3	Top	Steel	Phosphated	Med Gray	Apex Metal Stamping Co. Brooklyn, NY ?	'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
6	A ( Sideways )	1	3	Top	Steel	Phosphated	Med Gray	Apex Metal Stamping Co. Brooklyn, NY ?	Sideways 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
14	B G R	1	3	Middle	Steel	Phosphated	Lt Gray	Associated Spring Corp BGR Div. Detroit, MI	8.58mm wide 2.55mm high.
Version B Stripper Clips
18	SEY ( 7.71mm wide )	1	3	Top	Steel	Phosphated	Lt Gray	Seymour Products Co. Seymour, CT.	'SEY' 7.71mm wide 3.17mm (1/8 in.) high.
19	S E Y ( 9.42mm wide )	1	3	Top	Steel	Phosphated	Lt Gray	Seymour Products Co. Seymour, CT.	'SEY' 9.42mm wide 3.17mm (1/8 in.) high.
20	SEY ( Top of 'E' missing )	1	3	Top	Steel	Phosphated	Lt Gray	Seymour Products Co. Seymour, CT.	Top of 'E' missing 'SEY' 7.71mm wide 3.17mm (1/8 in.) high.
21	SEY ( Slanted )	1	3	Top	Steel	Phosphated	Lt Gray	Seymour Products Co. Seymour, CT.	Slanted 'SEY' 7.44mm wide 3.17mm (1/8 in.) high.
Version C Stripper Clips
3	A ( Hole in spring )	1	3	Top	Steel	Phosphated	Med Gray	Apex Metal Stamping Co. Brooklyn, NY ?	'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high. 2.77mm (7/64 in.) hole in spring
8	A ( Sideways ) ( Hole in spring )	1	3	Top	Steel	Phosphated	Lt Gray	Apex Metal Stamping Co. Brooklyn, NY ?	Miss-formed 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high. 2.38 (3/32in.) hole in spring
9	A ( Sideways ) ( Hole in spring )	1	3	Top	Steel	Phosphated	Lt Gray	Apex Metal Stamping Co. Brooklyn, NY ?	Miss-formed 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high. 2.77mm (7/64 in.) hole in spring
22	SEY ( Hole in spring )	1	3	Top	Steel	Phosphated	Lt Gray	Seymour Products Co. Seymour, CT.	'SEY' 8.28mm wide 3.57mm (9/64 in.) high. 2.38mm (3/32in.) hole in spring.
Version D Stripper Clips
4	A	1	3	Top	Steel	Phosphated	Med Gray	Apex Metal Stamping Co. Brooklyn, NY ?	'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
5	A	1	3	Top	Steel	Phosphated	Med Gray	Apex Metal Stamping Co. Brooklyn, NY ?	Small 'A' 1.98mm (5/64 in.) wide 2.38mm (3/32 in.) high.
7	A ( Sideways )	1	3	Top	Steel	Phosphated	Lt Gray	Apex Metal Stamping Co. Brooklyn, NY ?	Sideways 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
10	A ( Sideways )	1	3	Top	Steel	Phosphated	Lt Gray	Apex Metal Stamping Co. Brooklyn, NY ?	Miss-formed 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
11	A1	1	3	Top	Steel	Phosphated	Lt Gray	Apex Metal Stamping Co. Brooklyn, NY ?	'A' 3.17mm (1/8 in.) wide 3.96mm (7/32 in.) high.
12	A3	1	3	Top	Steel	Phosphated	Lt Gray	Apex Metal Stamping Co. Brooklyn, NY ?	2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
13	A O	1	3	Top	Steel	Phosphated	Med Gray	Associated Spring, Bristol, CT	Stylized 'A' 6.44mm wide 3.17 (1/8 in.) high.
15	G.G.G.	1	3	Top	Steel	Phosphated	Lt Gray	G. G. Greene Metal Stamping Co. Warren, PA	11.27mm wide 3.17mm (1/8 in.) high.
16	G.G.M.	1	3	Top	Steel	Phosphated	Lt Gray	G. G. Greene Metal Stamping Co. Warren, PA	12.01mm (1/2 in.) wide 3.57mm (9/64 in.) high.
17	LUFKIN	1	3	Top	Steel	Phosphated	Lt Gray	Lufkin Tool Company. Saginaw, MI	Lufkin stamped in a italic font 6.62mm wide 1.29mm hight of the 'ufkin'.
23	SEY ( 7.55mm wide )	1	3	Top	Steel	Phosphated	Lt Gray	Seymour Products Co. Seymour, CT.	'SEY' 7.55mm wide 3.17mm (1/8 in.) high.
24	SEY ( 7.55mm wide )	1	3	Top	Steel	Phosphated	Black	Seymour Products Co. Seymour, CT.	Blackened clip 'SEY' 7.55mm wide 3.17mm (1/8 in.) high. Unusual for US clips to have a black finish, very possible this clip has been refinished.
25	SEY ( 8.28mm wide )	1	3	Top	Steel	Phosphated	Lt Gray	Seymour Products Co. Seymour, CT.	'SEY' 8.28mm wide 3.17mm (1/8 in.) high.
Civilian Production Stripper Clips
1	None	2	4	Top	Stainless Steel	Stainless	Silver	J Clemmens, Davenport, Iowa	Blued springs (2) light and heavy
2	ClemSul	2	4	Top	Stainless Steel	Stainless	Silver	J Clemmens, Davenport, Iowa	Blued springs (2) light and heavy
Ser	Marking	No of Stops	End Profile	Stop Posn	Material	Finish	Colour	Manufacturer	Notes

Thank you to Noah Zark for IDing this previously 'Unknown' clip (A O) as being American.
Thank you to Peter Mackinven for the A1, G.G.M and black SEY examples.
Thank you to Phillip Owen for pointing out the diferences in the SEY markings and the new sub-variants shown.
Thank you to Peter Mackinven for the photo of the ClemSul marked clip and instruction leaflet.

PHOTOS

Version A Stripper Clips
A Large 'A' 3.96mm (5/32 in.) wide x 5.55mm (7/32 in.) high.	A Sideways 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.
A 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.	B G R 8.58mm wide x 2.55mm high.
Version B Stripper Clips
SEY 'SEY' 7.71mm wide x 3.17mm (1/8 in.) high.	SEY Top of 'E' missing 'SEY' 7.55mm wide x 3.17mm (1/8 in.) high.
SEY 'SEY' 9.42mm wide x .17mm (1/8 in.) high.	SEY Slanted 'SEY' 7.55mm wide x 3.17mm (1/8 in.) high.
Version C Stripper Clips
A (2.77mm (7/64 in.) hole in spring) 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.	A (2.77mm (7/64 in.) hole in spring) Sideways miss-formed 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.
A (2.38 (3/32in.) hole in spring) Sideways miss-formed 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.	SEY (2.38mm (3/32in.) hole in spring) 'SEY' 8.28mm wide x 3.57mm (9/64 in.) high.
Version D Stripper Clips
A 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.	G.G.G. 11.27mm wide x 3.17mm (1/8 in.) high.
A Small 'A' 1.98mm (5/64 in.) wide x 2.38mm (3/32 in.) high.	G.G.M. 12.01mm (1/2 in.) wide x 3.57mm (9/64 in.) high
A Sideways 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.	LUFKIN 6.62mm wide x 1.29mm hight of the 'ufkin'.
A Sideways miss-formed 'A' 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.	SEY 'SEY' 7.55mm wide x 3.17mm (1/8 in.) high.
A1 'A' 3.17mm (1/8 in.) wide x 3.96mm (7/32 in.) high.	SEY Blackend 'SEY' 7.55mm wide x 3.17mm (1/8 in.) high. Unusual for US clips to have a black finish, very possible this clip has been refinished.
A3 2.77mm (7/64 in.) wide x 3.57mm (9/64 in.) high.	SEY 'SEY' 8.28mm wide x 3.17mm (1/8 in.) high.
AO Stylized 'A' 6.44mm wide x 3.17 (1/8 in.) high.
Version D Stripper Clips
Civilian Production Stripper Clips
None (made by J Clemmens)	ClemSul (made by J Clemmens)

MEASUREMENTS

All measurements in millimeters

Version A Stripper Clips
Ser	Markings	Length	Width	Width with stops	Depth	Retainer length	Material Thickness	Retainer Holes		Spring Profile	Notes
								Height	Width
1	A	60.50	14.50	15.29	5.38	2.20	0.60	3.30	4.95		Large 'A' 3.96mm (5/32 in.) wide 5.55mm (7/32 in.) high.
2	A	60.41	14.49	15.19	5.38	2.27	0.52	3.82	5.12		'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
6	A ( Sideways )	60.49	14.50	15.25	5.43	2.50	0.53	3.55	5.00		Sideways 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
14	B G R	60.40	14.50	15.23	5.43	2.50	0.60	3.68	5.07		8.58mm wide 2.55mm high.
Version B Stripper Clips
18	SEY ( 7.71mm wide )	60.49	14.43	15.20	5.31	2.28	0.56	3.64	5.25		'SEY' 7.71mm wide 3.17mm (1/8 in.) high.
19	S E Y ( 9.42mm wide )	60.55	14.37	15.28	5.36	2.42	0.56	3.63	5.27		'SEY' 9.42mm wide 3.17mm (1/8 in.) high.
20	SEY ( Top of 'E' missing )	60.62	14.42	15.21	5.29	2.23	0.56	3.60	5.04		Top of 'E' missing 'SEY' 7.71mm wide 3.17mm (1/8 in.) high.
21	SEY ( Slanted )	60.61	14.43	15.32	5.22	2.17	0.53	3.59	5.02		Slanted 'SEY' 7.44mm wide 3.17mm (1/8 in.) high.
Version C Stripper Clips
3	A ( Hole in spring )	60.37	14.45	15.16	5.35	2.40	0.55	3.72	5.07		'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high. 2.77mm (7/64 in.) hole in spring
8	A ( Sideways ) ( Hole in spring )	60.62	14.53	15.25	5.47	1.99	0.55	3.60	5.04		Miss-formed 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high. 2.38 (3/32in.) hole in spring
9	A ( Sideways ) ( Hole in spring )	60.68	14.55	15.24	5.44	2.14	0.52	3.60	4.90		Miss-formed 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high. 2.77mm (7/64 in.) hole in spring
22	SEY ( Hole in spring )	60.49	14.41	15.24	5.30	2.19	0.55	3.60	5.00		'SEY' 8.28mm wide 3.57mm (9/64 in.) high. 2.38mm (3/32in.) hole in spring.
Version D Stripper Clips
4	A	60.41	14.40	15.09	5.38	2.20	0.55	3.65	5.12		'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
5	A	60.47	14.57	15.38	5.35	2.08	0.60	3.33	5.06		Small 'A' 1.98mm (5/64 in.) wide 2.38mm (3/32 in.) high.
7	A ( Sideways )	60.48	14.50	15.24	5.51	2.07	0.50	3.45	4.99		'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
10	A ( Sideways )	60.65	14.51	15.20	5.47	2.09	0.51	3.58	5.01		Miss-formed 'A' 2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
11	A1	60.47	14.44	15.36	5.33	2.45	0.49	3.75	5.05		'A' 3.17mm (1/8 in.) wide 3.96mm (7/32 in.) high.
12	A3	60.48	14.43	15.15	5.45	2.20	0.55	3.55	5.00		2.77mm (7/64 in.) wide 3.57mm (9/64 in.) high.
13	A O	60.24	14.50	15.23	5.30	2.50	0.55	3.72	4.94		Stylized 'A' 6.44mm wide 3.17 (1/8 in.) high.
15	G.G.G.	60.56	14.50	15.10	5.39	2.25	0.65	3.49	5.00		11.27mm wide 3.17mm (1/8 in.) high.
16	G.G.M.	60.29	14.49	15.10	5.38	2.27	0.65	3.25	5.00		12.01mm (1/2 in.) wide 3.57mm (9/64 in.) high.
17	LUFKIN	60.45	14.45	15.33	5.37	2.40	0.55	3.33	4.95		Lufkin stamped in a italic font 6.62mm wide 1.29mm hight of the 'ufkin'.
23	SEY ( 7.55mm wide )	60.23	14.45	15.20	5.30	2.20	0.65	3.61	5.23		'SEY' 7.55mm wide 3.17mm (1/8 in.) high.
24	SEY ( 7.55mm wide )	60.24	14.55	15.16	5.41	2.11	0.53	3.60	5.21		Blackened clip 'SEY' 7.55mm wide 3.17mm (1/8 in.) high. Unusual for US clips to have a black finish, very possible this clip has been refinished.
25	SEY ( 8.28mm wide )	60.19	14.50	15.29	5.37	2.45	0.52	3.67	5.26		'SEY' 8.28mm wide 3.17mm (1/8 in.) high.
Civilian Production Stripper Clips
1	None	60.50	14.53	16.01	5.49	2.59	0.49	3.29	5.03		Made by J Clemmens, Davenport, Iowa Blued spring
2	ClemSul	?	?	?	?	?	?	?	?		Made by J Clemmens, Davenport, Iowa Blued spring
Ser	Markings	Length	Width	Width with stops	Depth	Retainer length	Material Thickness	Height	Width	Spring Profile	Notes
								Retainer Holes
	Legend			Rounded corners				Rounded 45 degree corners			Sharp 45 degree corners

All measurements in millimeters

DID YOU KNOW

To aid in the stripping of the ammunition from the clip into the magazine the Combination Tool of the M14 cleaning kit could be used as a 'pusher' to help relive the strain to the thumb.