Frequently Asked Questions

The terms are interchangeable, but "suppressor" is more accurate. You cannot make a firearm completely silent. Suppressors reduce sound levels but do not eliminate them.

Both terms are legally correct and appear in ATF documentation. We prefer "suppressor" because it accurately describes what the device does.

A suppressor contains, slows, cools, and redirects the hot, high-speed gases exiting a firearm's muzzle when fired.

Inside the suppressor is a series of baffles that let the projectile pass through while deflecting, redirecting, and cooling the gases that contribute to the loud noise of a gunshot.

Note: A significant portion of the sound from many firearms is the supersonic crack of the projectile breaking the sound barrier. Suppressors cannot mitigate that crack. For the quietest shooting experience, use subsonic ammunition.

This depends on the firearm, suppressor, and ammunition. Suppressors reduce the noise of a gunshot by an average of 20-35 dB, roughly the same reduction as earplugs or earmuffs.

A suppressed .22 LR with subsonic ammunition is the quietest combination. A suppressed centerfire rifle with standard ammunition will still be loud but typically hearing safe (below 140 dB).

Despite what movies show, suppressors do not make firearms whisper-quiet. They make them safer for your hearing.

Yes, with limitations. A larger caliber suppressor can suppress smaller caliber firearms if you have the appropriate adapters or mounts.

For example, a .30 caliber suppressor can be used on .223/5.56, 6mm, .300 Blackout, and .308 rifles. A .45 caliber pistol suppressor can suppress 9mm and .40 S&W handguns.

Using a larger caliber suppressor is not as efficient as one made for the specific caliber, but it still provides significant sound reduction, and some may say the difference is negligible. Many shooters buy multi-caliber suppressors for versatility and we recommend that for your first suppressor.

Three common mounting methods:

• Direct thread - Screws directly onto a threaded barrel. Simplest, lightest, and shortest option.
• Quick detach (QD) - Uses a muzzle device (flash hider or brake) as a mount. Faster attachment/removal and easy transfer between hosts.
• Piston/booster - Required for tilting-barrel pistols (Glock, Sig, etc.) to allow proper cycling with the added weight.

Some suppressors are integral to the firearm itself, built into the barrel for maximum suppression.

Weight Comparison:

Material	Density	Typical Weight
Titanium	4.43 g/cm³	8-12 oz (lightest)
Stainless Steel	7.8-8.0 g/cm³	14-20 oz
Inconel	8.2-8.4 g/cm³	15-21 oz (heaviest)

Titanium is approximately 40% lighter than stainless steel for equivalent strength.

Maximum Operating Temperatures:

Material	Practical Temp Limit	Full-Auto Rating
Titanium	~800°F	Limited (often 10"+ barrel restrictions)
Stainless Steel	~1,400°F	Excellent
Inconel	1,200°F+	Best - no restrictions

Grade 5 Titanium loses significant structural strength above 800°F and is not recommended for high-volume sustained fire.

Recommended Use Cases:

Application	Recommended Material
Full-auto/belt-fed	Inconel
Military/LE hard use	Inconel or 17-4 SS
Hunting/precision bolt rifles	Titanium
General semi-auto	Any (titanium for weight savings)
Budget/value	Stainless Steel
Night vision use	Inconel (minimal flash signature)

Cooling Behavior: Despite lower thermal conductivity, titanium suppressors cool fastest in practice. Lower thermal mass means less material retaining heat. A titanium suppressor heats up faster per round but returns to ambient temperature quicker.

Inconel maintains the most consistent dimensional stability across temperature ranges, important for maintaining point-of-impact consistency during sustained fire.

It depends on the suppressor type:

• Rimfire suppressors (.22 LR) - Require regular cleaning due to lead and carbon buildup. Most are user-serviceable with removable baffles.
• Centerfire rifle suppressors - Generally sealed and self-cleaning through high heat and gas pressure. Require little to no maintenance.
• Pistol suppressors - Vary by design. Some are sealed, others are user-serviceable.

For suppressors that need cleaning, solvents like CAT206 (titanium and Inconel only), HUXWRX Suppressor Sauce, or MIL-COMM Suppressor X work well. Always remove non-metal parts (o-rings, wipes) before using solvents.

An end cap strike (or baffle strike) occurs when a bullet contacts the suppressor's internal baffles or end cap instead of passing cleanly through. This damages the suppressor and can be dangerous.

Causes and prevention:

• Improper installation - Ensure the suppressor is fully tightened and the muzzle device is properly torqued.
• Concentricity issues - The barrel threads must be concentric with the bore. Use an alignment rod to check before first use.
• Loose muzzle device - Check torque regularly, especially on QD mounts.
• Damaged crown - A damaged barrel crown can cause bullet instability.

End cap strikes are not common when parts are properly installed and aligned.

Not necessarily. Supersonic ammunition still benefits from a suppressor because the muzzle blast is reduced. The sonic crack occurs downrange and is less disruptive than the blast at the shooter's ear.

Subsonic ammunition eliminates the sonic crack entirely, resulting in quieter overall noise. It is a personal preference depending on your priorities.

For the quietest possible shooting, use subsonic ammunition. For hunting or defensive applications where bullet performance matters, supersonic ammunition with a suppressor still provides significant hearing protection.

Generally, no. Most shooters report no change or slight improvement in accuracy with a suppressor. The reduced recoil and muzzle rise can make follow-up shots easier.

Point of impact may shift slightly when adding or removing a suppressor. Zero your firearm with the suppressor attached if you plan to shoot suppressed regularly.

If registered to you as an individual, you must be present when others use your suppressor.

If registered to a trust, any trustee can possess the suppressor independently. This is one of the main advantages of trust ownership for families or shooting partners.

Suppressors can be inherited. The inheritor must file ATF Form 5 (tax-exempt transfer to heir) and pass a background check. No tax is due on inheritance transfers.

Trust-owned suppressors transfer according to the trust terms. Individual-owned suppressors transfer through estate proceedings.

Yes. Private sales of suppressors require the buyer to complete a Form 4, just like a new purchase. The suppressor must remain with you until approval. You cannot hand-deliver a suppressor to a buyer without going through the Form 4 process.

The ATF recommends keeping a copy available when using your suppressor. The approved Form 4 serves as your registration document. A digital copy on your phone is generally acceptable.

Some ranges may request to see registration documentation.

Suppressors are legal in 42 states:

Alabama, Alaska, Arkansas, Arizona, Colorado, Connecticut, Florida, Georgia, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming

Not legal for private ownership: CA, DE, DC, HI, IL, MA, NJ, NY, RI

SBRs are legal in most states, with some restrictions:

Alabama, Alaska, Arkansas, Arizona, Colorado, Connecticut*, Delaware*, Florida, Georgia, Idaho, Illinois**, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland*, Massachusetts, Michigan*, Minnesota*, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania*, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington*, West Virginia, Wisconsin, Wyoming

State-specific notes:

• CT, MD, WA: Must comply with state assault weapon bans
• DE: Prohibited in Wilmington
• IL: C&R FFLs only
• MI, PA: Cannot ship to residence (FFL required)
• MI: May require local registration
• MN: Consult state-level laws

SBS ownership is legal in these states:

Alabama, Alaska, Arkansas, Arizona, Colorado, Connecticut*, Florida, Georgia, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland*, Massachusetts, Michigan*, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Wisconsin, West Virginia, Wyoming

State-specific notes:

• CT, MD: Must comply with state assault weapon bans
• MI: May require local registration

Pre-1986 transferable machine guns are legal in these states:

Alabama, Alaska, Arkansas, Arizona, Colorado, Florida, Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Maine, Maryland*, Massachusetts**, Michigan*, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont*, Virginia, West Virginia, Wisconsin*, Wyoming

State-specific notes:

• MA: Special license required
• MD: Consult state law and assault weapon ban
• MI: May require local registration
• VT: Must be registered with state
• WI: Rifle cartridges only

You can own an NFA item if you:

• Are a U.S. citizen or legal permanent resident
• Are at least 21 years old (to purchase from a dealer)*
• Can legally purchase a handgun
• Live in a state that allows NFA ownership
• Pass an ATF background check

*Individuals 18-20 can possess NFA items through a trust or corporation, or purchase privately.

No. This is a common misconception.

You do not need any license to own a suppressor, SBR, or other NFA item. You need to:

• Complete ATF Form 4
• Pass a background check
• Wait for ATF approval

A "Class 3" license (actually a Special Occupational Tax) is for dealers who buy and sell NFA items as a business. The ATF can inspect dealers, but buying a suppressor does not give up any rights or invite inspections.

In most suppressor-legal states, yes. 41 states allow hunting with suppressors. The exception is Connecticut, which allows ownership but prohibits hunting use. Check your state's hunting regulations for specific requirements.

Suppressors and AOWs: You can travel freely to any suppressor-friendly state. No ATF notification required. When flying, declare your suppressor as a firearm at check-in.

SBRs, SBSs, machine guns, and destructive devices: You must get ATF approval before crossing state lines. Submit Form 5320.20 to:

BATFE NFA Branch
244 Needy Road
Martinsburg, WV 25405

Or submit via email: [email protected]
Or fax: (304) 616-4501
Or through eForms.atf.gov

ATF approval typically takes 14-22 days and must be received before travel. If you regularly travel to the same location (hunting property, competition venue), ATF can approve transportation for up to one year.

Yes. We ship NFA items to all 42 suppressor-friendly states.

We handle the entire process remotely, from electronic Form 4 submission to direct-to-door delivery. You never need to visit our Texas location or find a local dealer.

No. Unlike other dealers, we do not charge transfer fees or paperwork processing fees.

Your final cost includes:

• Suppressor price
• ATF transfer tax - now $0!
• Applicable sales tax
• Shipping

All fees are displayed in your cart before checkout.

When you buy from Capitol Armory, you save time and money compared to the traditional transfer process.

Traditional Process (buying online, transferring to local FFL):

• Pay for the suppressor
• Pay ATF transfer tax
• Pay local dealer transfer fee (typically $75-$150)
• Visit dealer to complete paperwork
• Return to dealer for fingerprints
• Return to dealer after approval to pick up
• Total dealer visits: 3+

Capitol Armory Process:

• Pay for the suppressor
• Pay ATF transfer tax
• No dealer transfer fees
• Complete paperwork online from home
• Submit fingerprints digitally or by mail
• Suppressor ships to your door after approval
• Total dealer visits: 0

You save: $75-$150 in transfer fees, plus time and fuel costs from multiple dealer visits.

We store your fingerprints securely for future purchases, making your next suppressor even faster to process.

NFA Items (suppressors, SBRs, etc.):

New customers receive detailed instructions within one business day on completing your profile and submitting fingerprints. Existing customers receive DocuSign paperwork within two business days.

Firearms:

Note your preferred FFL in the order comments. Your dealer sends their FFL to [email protected]. We ship within 24 hours of receiving their license.

Accessories:

Your order ships same day (or next business day if ordered after mail pickup). Tracking information is emailed automatically.

We do not currently offer layaway or financing options. Payment in full is required at checkout.

No. The suppressor must remain with the dealer until your Form 4 is approved. You cannot take possession or use the suppressor during the waiting period.

No. When you purchase your next suppressor, you will still need to complete the ATF application process and wait for approval.

However, Capitol Armory keeps your fingerprints and photo on file. This makes preparing your application for future purchases fast and simple. Repeat customers typically skip straight to the signature step.

eForm applications: The ATF notifies both you and Capitol Armory. We email you approval details the same day.

Paper applications: The ATF notifies Capitol Armory. We forward your approval via email immediately.

Once approved, we contact you about delivery options.

Because the dealer submits the form, not you.

When you purchase an NFA item, Capitol Armory submits your Form 4 through our ATF eForms account. The application appears in our eForms dashboard, not yours. Your personal ATF eForms account only shows forms you submit yourself (like Form 1 applications to manufacture).

This is by design. The dealer is the "transferor" filing the application to transfer the item to you.

What you will receive:

• Email notification from ATF when your form status changes to "Submitted"
• Email with approved PDF upon approval

How to check status:

Call ATF directly at (304) 616-4500 with:

• Your name (or trust/corporation name)
• Serial number of the suppressor
• Dealer name (Capitol Armory)

ATF can only confirm if you are in the system and provide a general status update.

The process depends on what type of NFA item you own:

Suppressors and AOWs: You can move freely to any suppressor-friendly state. No ATF approval or notification is legally required before moving.

SBRs, SBSs, machine guns, and destructive devices: You must obtain ATF approval before moving. Submit ATF Form 5320.20 (Application to Transport Interstate) and wait for written approval. Do not move the item until you receive it. Processing typically takes 2-4 weeks, though it can extend longer during high-volume periods.

Critical consideration: ATF will only approve Form 5320.20 if possession is legal in your destination state. If your new state prohibits the specific NFA item, you must either leave it with a trustee in your original state, store it securely with someone legally permitted to possess it, or transfer/sell it before moving.

No ATF approval or notification is legally required for intrastate moves with any NFA item, including suppressors, SBRs, SBSs, machine guns, or destructive devices.

Who must file: Any individual (non-FFL/SOT) who plans to transport a machine gun, SBR, SBS, or destructive device across state lines, whether permanently or temporarily.

When required:

• Moving your SBR to a new state (permanent relocation): Yes
• Taking your SBR on a hunting trip to another state: Yes
• Competing in another state with your SBR: Yes
• Moving within the same state: No (but recommended for record updates)

When NOT required:

• Suppressors and AOWs are exempt from Form 5320.20 requirements. You can transport them interstate without prior approval.

Processing time: Typically 14-22 days, though it can extend to 4+ weeks during busy periods. Plan accordingly as the approval must be received before transport.

One-year approval option: If you regularly travel to the same location (hunting property, competition venue), ATF can approve transportation for up to one year. Indicate this on your application.

Submission methods:

• Email: [email protected]
• Fax: (304) 616-4501
• Mail: Bureau of ATF, NFA Division, 244 Needy Road, Martinsburg, WV 25405
• eForms.atf.gov

This is one of the most complex scenarios in NFA transfers. Your options depend on how you filed:

If you move within the same state: Your pending Form 4 is generally unaffected. Update your address on your government-issued state ID.

If you move out of state with an NFA trust: If another responsible person on your trust remains in the original state, they can pick up the item once approved. The trust maintains legal possession, and the item can later be transported to your new state.

If you move out of state as an individual (or no trust member remains): You will likely need to:

• Contact Capitol Armory immediately
• We will cancel/withdraw the pending application
• File a new Form 4 in your current state

Bottom line: If you anticipate a move during your approval wait, contact us immediately. An NFA trust with multiple responsible persons in different states provides the most flexibility for this situation.

NICS Delay:

A "Delayed" response means the FBI needs additional time to research your background. Common causes include common name matches, incomplete records, or prior arrests requiring disposition verification.

For NFA transfers: Unlike standard retail transfers, there is no automatic "proceed" after 3 business days. Your Form 4 remains pending until the NICS check resolves. This can take weeks to months, depending on the complexity.

What to do:

• Wait for resolution (most delays clear within a couple of months)
• Capitol Armory and the ATF will notify you when your status changes
• Consider applying for a UPIN (see below) to prevent future delays

NICS Denial:

A "Denied" response means the FBI identified information indicating you may be a prohibited person under federal law.

What happens:

• ATF NFA Division disapproves your application
• You receive a letter explaining the denial and appeal process
• The letter includes your NICS Transaction Number (NTN) needed for appeal

Appeal process:

• Submit a "Firearm Related Challenge" through the FBI NICS website
• Provide your NICS Transaction Number
• May require submission of additional fingerprints
• FBI reviews records for accuracy
• Processing: Weeks to months depending on complexity

Website: fbi.gov/services/cjis/nics

Voluntary Appeal File (VAF) / UPIN:

If you experience repeated delays due to common name matches or prior record issues, apply for a Unique Personal Identification Number (UPIN):

• Submit VAF application: fbi.gov/file-repository/vaf-form-25.pdf
• Provide fingerprints with application
• Upon approval, receive UPIN
• Include UPIN on future Form 4473s and NFA applications

A UPIN helps prevent erroneous delays by linking your verified identity to your background check.

We will refile after you appeal or obtain a UPIN.

For home delivery, we handle the ATF compliance requirements:

• Complete Form 4473 electronically
• Submit a copy of your government-issued ID
• Sign a delivery affidavit

We issue CLEO notification and observe the required 7-day waiting period. Your suppressor ships via USPS after the waiting period.

Total time from approval to delivery: approximately 2 weeks.

Adult signature is required at delivery, but it does not necessarily have to be the purchaser.

Requirements:

• Must be an adult (21 years or older)
• Carriers (UPS, USPS) require "Adult Signature Required" and "Direct Delivery Only" services
• NFA items cannot be shipped to PO Boxes
• Packages cannot be left without signature

Who can sign: Any adult at the delivery address can sign: spouse, family member, roommate. The carrier verifies the recipient is 21+ but does not verify the specific identity against the Form 4.

If no one is available: The carrier will attempt redelivery or hold the package at a local facility for pickup. They should never leave an NFA item without an adult signature.

Active duty military can establish residency in the state of their permanent duty station and/or their home state, giving them flexibility for NFA purchases.

Required documentation to establish duty station residency:

• Current government-issued photo ID
• Permanent Change of Station (PCS) orders (paper or electronic)
• Government document showing current residential address

Which address to use on Form 4473:

• Living on base: Use permanent duty station address
• Living off-base in same state as duty station: Use current residence address

Removing a trustee/co-trustee:

• Execute a formal trust amendment. Use the auxiliary trustee removal amendment provided with our NFA Trust.
• Keep the original amendment with your trust documents
• At the time of your next purchase, provide Capitol Armory any executed amendments

ATF notification requirements:

You are not required to notify ATF when making changes to your trust, unless an item is pending.

What happens to registered items: NFA items remain registered to the trust, not to individual trustees. Removing or adding trustees does not affect the registration status. No new Form 4 or transfer tax is required when changing trustees.

Critical warning: Once removed, a former trustee cannot legally possess any trust NFA items. Possession by a non-trustee constitutes illegal possession of an NFA firearm under 26 U.S.C. § 5861. Upon divorce or trustee removal, ensure the removed party no longer has access to any NFA items and that all items are physically secured by remaining trustees.

No. Beneficiaries do not submit fingerprints or photographs.

The key distinction:

Role	Fingerprints/Photos Required?	Can Possess NFA Items?
Settlor/Grantor	Yes	Yes
Trustee/Auxiliary Trustee	Yes	Yes
Successor Trustee	No (until they become active)	No (until activated)
Beneficiary	No	No (until inheritance)

Regulatory definition: ATF defines "responsible person" as someone who "possesses, directly or indirectly, the power or authority to direct the management and policies of the trust...to receive, possess, ship, transport, deliver, transfer, or otherwise dispose of a firearm."

ATF explicitly states: "An example of who may be excluded from this definition is the beneficiary of a trust, if the beneficiary does not have the capability to exercise the powers or authorities enumerated."

What beneficiaries are: Individuals who will inherit trust property upon the settlor's death. They have no current rights to possess, use, or control NFA items.

Warning about poorly-drafted trusts: Some trusts give beneficiaries additional powers (like current possession rights) that would make them "responsible persons" requiring fingerprints and photos. Review your trust documents carefully. The Capitol Armory NFA Firearms Trust is designed to clearly distinguish between beneficiaries and responsible persons to avoid this issue.

Yes. An 18-year-old can be added as a trustee and legally possess and use NFA items held by the trust.

The key distinction is purchase vs. possession:

Activity	Minimum Age
Possess NFA firearm	18
Purchase from FFL dealer	21
Make (Form 1)	18
Purchase privately (in-state)	18

How it works: The National Firearms Act does not specify a minimum possession age. ATF has issued determinations confirming that while individuals must be 21 to purchase NFA firearms through a dealer, they can own and possess NFA firearms at 18 years old.

Practical application: Add your 18-year-old as a co-trustee on your NFA trust. They can legally possess and use any NFA items held by the trust. However, they cannot personally pick up items from a dealer until age 21. Another trustee (21+) must complete the dealer transfer, after which the 18-year-old co-trustee can freely possess the item.

Requirements for adding an 18-year-old trustee:

• Must be 18 years or older (not a minor)
• Must be legally able to possess a firearm (no prohibiting factors)
• Must submit fingerprints, photo, and Form 5320.23 for each new NFA application
• Must pass ATF background check

The trust document itself: No formal amendment is required when you move.

ATF notification:

• Interstate moves with SBRs/SBSs/MGs/DDs: Form 5320.20 approval required before moving (same as individuals)
• Interstate moves with suppressors/AOWs: No approval required
• Intrastate moves: No legal requirement to notify

Yes, you can add any suppressor to a trust after you buy it by filing as an individual. This requires filing an ATF Form 4 to transfer the item from yourself to the trust, along with paying the transfer tax again.

If you think you may want to share your suppressors with family members or want the estate planning benefits of a trust, consider filing on a trust from the start.

Form 3 transfers NFA items between licensed dealers. These transfers:

• Require no tax payment
• Process faster than Form 4s
• Do not require fingerprints or photos

We use Form 3 to transfer inventory between our location and manufacturers.

eForm is the ATF's digital submission system. Benefits include:

• Faster processing times
• Digital signatures (no wet signatures required)
• Electronic fingerprint submission
• Real-time status tracking

Capitol Armory uses eForm for all transfers unless you request paper filing.

FFL (Federal Firearms License): Authorization to engage in the business of buying and selling firearms.

SOT (Special Occupational Taxpayer): An FFL who has paid additional tax to deal in NFA items. Only FFL/SOTs can buy, sell, and transfer suppressors and other NFA items.

Capitol Armory is a licensed FFL/SOT dealer in 42 suppressor-friendly states.

NFA stands for National Firearms Act (1934), the federal law regulating certain firearms and accessories.

NFA items include:

• Suppressors (silencers)
• Short barrel rifles (SBRs) - rifles with barrels under 16"
• Short barrel shotguns (SBSs) - shotguns with barrels under 18"
• Machine guns (fully automatic firearms)
• Destructive devices (DDs)
• Any other weapons (AOWs)

These items are also called "Class 3" or "Title II" weapons.