2027 Forest River Sandstorm 4017GX vs Jayco Seismic 399
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Key differences
Both are 2027 Fifth-wheel toy hauler models. Here's how they differ, from manufacturer specifications.
- The Jayco Seismic 399 is 2″ longer: 45′ 2″ vs 45′.
- The Jayco Seismic 399 is 89 lb lighter unloaded: 15,585 vs 15,674 lb.
- The Jayco Seismic 399 lists 89 lb more cargo capacity: 5,415 vs 5,326 lb.
- The Jayco Seismic 399 has a 500 lb lighter hitch weight: 3,265 vs 3,765 lb.
- The Forest River Sandstorm 4017GX holds 44 gal more fresh water: 150 vs 106 gal.
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YOUR SHORTLIST
Floorplan
PRICING
Manufacturer price (USD)
Not verified
$134,243Starting MSRPChecked 2026-10-23 · Price source
Lowest tracked dealer price (USD)
No recently verified dealer price
No recently verified dealer price
Est. monthly payment (USD)
No verified price to estimate from
$1,086/mo20 years at 8.99% APR with 10% down, based on the MSRP. Before tax and fees.Customize this payment
DIMENSIONS & WEIGHTS
Exterior length
45′ 0″
45′ 2″
Garage length
—
13′ 6″
Exterior width
8′ 6″
8′ 6″
Exterior height
13′ 6″
13′ 3″
Shipping / unloaded weight
15,674 lb
15,585 lb
GVWR
21,000 lb
21,000 lb
Listed cargo capacity
5,326 lb
5,415 lb
Listed hitch weight
3,765 lb
3,265 lb
LIVING & SLEEPING
Sleeping capacity
—
8
Slide-outs
3
—
Main bed
Not verified
Not verified
Bunk beds
Not verified
Not verified
Dinette
Not verified
Not verified
Bathroom
Not verified
Not verified
Refrigerator
Not verified
Not verified
TANKS & EVERYDAY FEATURES
Fresh water
150 gal
106 gal
Gray water
120 gal
87 gal
Black water
80 gal
87 gal
Awning length
10′ 10″
21′ 0″
Shore power / electrical service
Not verified
Not verified
Solar equipment
Not verified
Not verified
Outdoor kitchen
Not verified
Not verified
Washer/dryer prep
Not verified
Not verified
Microwave
Not verified
Not verified
Cooktop
Not verified
Not verified
Air conditioning
Not verified
Not verified
Electric fireplace
Not verified
Not verified
Backup camera
Not verified
Not verified
Propane tanks
—
—
Tire size
Not verified
ST215/75R17.5'H'
SOURCES & VERIFICATION
Weight basis
Manufacturer unloaded vehicle weight
Manufacturer unloaded vehicle weight
Source checked
2026-10-23 Manufacturer ↗
2026-10-23 Manufacturer ↗
Which RVs are on your shortlist?
Choose from 2,320 RVs by Forest River, Keystone, Coachmen, Jayco and 21 other manufacturers. Add up to six to see their floorplans and specifications together.
Manufacturer floorplan images © their respective manufacturers. Specs checked October 19, 2026; exact-unit labels and production options may differ. “Not verified” or a dash means we have no confirmed value. “Not listed” means the applicable manufacturer equipment was checked but does not mention the feature; it does not mean “No.” “Conflicting data” means manufacturer entries disagree. “Optional” equipment is available but is not confirmed as standard. Camera prep does not confirm an installed camera. Weights are kept separate: unloaded weight, GVWR, cargo capacity, and hitch weight. Confirm every specification for the exact model year and configuration with the manufacturer. This tool does not establish towing compatibility.
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