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B5 Systems
Overview
The B5 Systems Government Issue Sopmod Stock is a collapsible stock designed for Mil-Spec buffer tubes, providing builders with a reliable and adjustable option for their AR-15 platforms. Made from durable polymer, this stock enhances the overall ergonomics of your setup while allowing for easy length adjustments to accommodate different shooting styles or user preferences. This stock is commonly found in builds featuring a Mid-Length gas system chambered in 5.56 NATO, making it a practical choice for a wide range of applications.
B5 Systems Government Issue SOPMOD Stock Collapsible Mil-Spec Black
B5 Systems Government Issue SOPMOD Stock Collapsible Mil-Spec Black was the fifth most added stock on GunPartPicker in August 2026, behind the Magpul AR-15 CTR Stock Collapsible Mil-Spec Black, with about 4% of all stocks and braces added to builds. Down from #4 in July. Builds with this stock are mostly chambered in 5.56 NATO (88%, then .223 Wylde 13%), mostly on mid-length gas (65%, then carbine-length 24%), and nearly all AR-15.
Availability is good: it was in stock at one retailer or another nearly every day in August 2026, and today 6 of the 7 retailers we track have it in stock. It dipped to $83.60 at Optics Planet for a stretch in August 2026, well under its usual $95, so sales do come around. Buying today, the lowest price is $95 at Brownells, above August's low of $83.60, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 31 retailers
We ranked every stock & brace by how often it shows up in real builds on GunPartPicker.
Read the guide: AR-15 Stock Popularity Report →Check it against the live catalog:
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Aggregated and anonymized data showing how builders use this product
Builds in the community that include the B5 Systems Government Issue Sopmod Stock Collapsible Mil-Spec Blk
| Build | Parts | Total |
|---|---|---|
 | 13 | $3466.60 |
 | 19 | $1168.28 |
 | 21 | $2639.38 |
 | 20 | $2317.15 |
 | 27 | $2979.31 |
 | 27 | $4054.48 |
 | 20 | $3663.06 |
 | 27 | $2122.96 |
 | 19 | $2034.51 |
 | 20 | $6931.10 |
 | 21 | $3146.04 |
 | 21 | $2957.35 |
2 global ratings
Top reviews
B5 SOPMOD stock is the same general profile as the issued LMT SOPMOD. Cheek weld is comfortable. Lock lever was stiff for the first week of adjustments before easing up. Now slides cleanly to each position.
B5 Systems Government Issue SOPMOD stock in black has the QD socket that holds a sling tight under load. Stock locks at each position positively on a milspec tube. Polymer is dense and durable - holds up to abuse. Authentic SOPMOD geometry.
