HGM724 vs HGM825: Which Echelon PDW Grip Module Is Right for You?

You already know the Echelon is worth building. The question is which platform to build it on.

Both the HGM724 and HGM825 are purpose-built PDW grip modules for the Springfield Armory Echelon — direct COG drop-in, no modifications, no gunsmithing. Both share the same core DNA: A.I.M.R. mag release, ambidextrous gas pedals, direct top-rail optic mount, Straight Jacket grip texture, and PA11 nylon construction with a 7075 aluminum charging handle included. Neither is the "budget" option. They are two different answers to two different builds.

Here is what actually separates them.

The Sharpest Differentiator: Suppressor Clearance

If you are running a can, start here.

HGM724: Max suppressor diameter is 1.05" (or larger with a 1" barrel extension). The dual monolithic M-Lok shroud wraps the front of the module, which is what gives the HGM724 its clean lines and accessory real estate — and it is also what sets the clearance ceiling. Most Obsidian 9 and compact 9mm cans fit comfortably. If you are running a larger-diameter suppressor, check your can's diameter before you order.

HGM825: Max suppressor diameter is 1.35" (or larger with a 1" barrel extension). The shroudless design is the reason. Without a front shroud, the 825 opens up the full bore envelope, which is why it can accommodate bigger cans. If you are running an Omega 9K, a Hybrid 46, or anything in the 1.1"–1.35" range, the HGM825 is the module that fits.

This is the decision point for most buyers who run suppressors. Know your can's diameter. If it clears on the HGM724, you are not giving anything up by going that route. If it does not, the HGM825 is your module.

Barrel Compatibility: The 4.0" Question

HGM724: 4.5" barrel only.

HGM825: 4.0" and 4.5" barrels, in standard, threaded, comped, ported, or suppressed configurations.

If you are on the 4.0" Echelon platform — or planning to be — the HGM825 is your only option here. This is a hard compatibility line, not a preference. The HGM724 was engineered around the 4.5" platform.

One compatibility note for HGM825 owners on the 4.0" platform: the HGM825 does not work with 4.0" 15-round magazines. You will need the full-size 17- or 20-round magazines.

Shroud vs. Shroudless: More Than a Suppressor Clearance Story

The HGM724's dual monolithic M-Lok shroud is a meaningful difference beyond bore clearance. The front shroud gives you M-Lok slots on the top and sides, so you can run a light, laser, sling mount, or any M-Lok accessory without adding a separate rail section. The front shroud is reinforced with a stainless steel inner shroud where it matters most for durability.

The HGM825 takes the opposite approach: no shroud, maximum barrel access, and the same ambidextrous M-Lok accessory capability on the main body. The platform is lighter in front, which some shooters prefer for balance on a PDW-length build.

Neither is objectively better. The HGM724 shroud gives you more real estate for accessories. The HGM825 shroudless design gives you more barrel configuration freedom.

Size and Weight

Both modules are close in overall length:

	HGM724	HGM825
Overall length	11.5"	11.25"
With Heighth stock deployed	21.75"	21.5"
Length of pull (Heighth stock)	16.5"	16.5"
Rail standard	M-Lok	M-Lok
Body material	PA11 Nylon	PA11 Nylon
Charging handle	7075 aluminum, Type III hardcoat	7075 aluminum, Type III hardcoat

The HGM825 is a quarter-inch shorter in the collapsed position. At this size class, that difference is negligible for most purposes, but it is real if you are fitting into a specific bag or case with tight tolerances.

What Is the Same on Both

So you are not choosing one and missing the other on these:

• Drop-in COG installation, no modifications

• A.I.M.R. (Auto Indexing Mag Release) — the front mag release drops the mag and auto-indexes your index finger to the bullet end of the magazine for faster reloads

• Ambidextrous gas pedals, built in on both sides

• Direct top-rail optic mount, lower than standard risers

• Straight Jacket grip texture — engineered for purchase under stress, in wet conditions, and with gloves

• PA11 nylon construction

• Precision-machined 7075 aluminum charging handle included

• Made in the USA

• M-Lok rail compatibility

Choose the HGM724 if...

• You are on the 4.5" Echelon platform

• Your suppressor is 1.05" diameter or smaller (most compact 9mm cans)

• You want M-Lok accessory slots on the front shroud for a light or laser without a separate rail section

• You want the shroud's clean integrated look

Choose the HGM825 if...

• You are on the 4.0" Echelon platform (the only compatible option for this barrel length)

• Your suppressor diameter exceeds 1.05" — anything up to 1.35"

• You are running or planning to run a larger-format suppressor

• You want the maximum barrel configuration flexibility (comped, ported, suppressed across both barrel lengths)

• You want the lighter, cleaner front end of a shroudless design

One More Thing: The Bundle Deal

Both modules qualify for the same $15 discount when you add a stock to your order at checkout. If you are planning to run the Heighth 9" slimline stock, stack the discount either way.

Ready to build? Shop the HGM724 at heighthdefense.com/product-page/hgm724 or the HGM825 at heighthdefense.com/product-page/hgm825.