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.17 HMR Frequently Asked Questions

Below are some of the most frequently asked questions we receive about our .17 HMR upper receivers and rifles. If you have a question that is not answered here, feel free to ask us and we will respond to you as soon as possible.

Q1. Isn't the .17 HMR cartridge unsafe to use in semi-automatic weapons?

No, it is not. This is a common misconception based primarily on the reputation of a select few, failed semi-automatic .17 HMR rifle designs as well as certain statements made by popular information sources in response. These statements were propagated throughout the firearms community and gradually became interpreted to mean that the .17 HMR cannot safely be used in semi-automatic rifles. Poor design and performance of these earlier rifles by other manufacturers resulted in relatively unsafe and unreliable weapons.

The .17 HMR cartridge is not inherently unsafe to use in a semi-automatic rifle. It simply is unsafe to use in a semi-automatic rifle that is not designed to fire it properly and in a safe manner. We have proven its capabilities by utilizing correct design techniques in critical areas of the weapon. We have been manufacturing and selling our .17 HMR weapon systems since late-2011 with great success. Our .17 HMR rifle's reputation is backed by excellent reviews from professionals, dealers, and retail customers across the country. Please consider this review of our rifle featured in the May/June 2012 edition of Rifle Shooter magazine, for one example. Also, please see a statement by Steve Hornady regarding this very subject of safety.

Q2. What ammunition do you recommend using in the .17 HMR?
  The rifle was designed to operate with all good-quality .17 HMR ammunition. The 17-grain and 20-grain types run best, but the new lead-free ammunition will also function. Ammunition must be essentially new as certain older batches were problematic. We normally say to use ammunition no older than one year that is manufactured by Hornady, CCI, Federal, or Winchester. To be clear, the weapon cannot use ammunition other than specifically .17 HMR.
Q3. I have some older .17 HMR ammunition. Can I use it?
  With older ammunition, there is a potential problem with quality and rim cracking. Our advice is to avoid this when possible. However, if you have ammunition that runs well and does not exhibit problems in this rifle, then it is safe to use it.
Q4. What target-type triggers do you recommend using in the .17 HMR?
  As currently designed, our . 17 HMR rifle is balanced to operate properly with a full-weight hammer and full-weight hammer spring typical of the stock semi-automatic parts. Specifically, this includes the round-top hammer profile and not the earlier notched front profile. Therefore, target-style fire control groups - specifically those with reduced hammer weight and reduced hammer spring weight - typically will not be suitable as the increased bolt speed will create a number of reliability issues. For those wishing to reduce the trigger pull weight for the .17 HMR rifle, it is possible to substitute either the Alexander Arms® or the Geissele SSA trigger groups with the addition of the aftermarket heavy buffer unit now available on our web site. We hope to be able to recommend alternative fire control groups in the future, as time permits for reliability testing. Again, we would like to emphasize that using alternative fire control groups without properly balancing the gun through the installation of heavy buffer units will lead to function problems. Additional details can be found in our .17 HMR Trigger Function Notice.
Q5. Is there a break-in period for the .17 HMR?
  Yes, there is a break-in period. Like any mechanical device, the rifle must be run in a well-lubricated condition for around 200 rounds before all of the contact surfaces have smoothed out. During the break-in period, correct lubrication and cleaning of the rifle will dramatically reduce problems both at this time and later.
Q6. Are additional magazines available for the .17 HMR?
  Yes, magazines can be ordered in the Online Store.
Q7. My magazine has split. What should I do?
  Typically, it is not possible to repair a magazine that has split and such an item should be replaced with a new unit. Magazines will wear with time and should be replaced on a periodic basis regardless of whether or not they are damaged. Occasionally, rough handling or
Q8. How should I clean my magazine?
  It is not recommended to disassemble the magazine for regular cleaning. Firing residue may be removed from the follower and magazine lips using either a small cloth or cotton swab and the Mili-tec oil or Break-Free® CLP®.
Q9. I have experienced a split rim and the magazine was damaged. What should I do?
  The magazine actually forms part of the safety system for the rifle. Magazines are manufactured from acrylic plastic, are stitch-welded, and have a clip-on base plate. In the event of a split rim, the magazine may break such that all remaining live rounds are not contained within the rifle. This weak link may, on occasion, fail without any particular cause and the magazine will need to be replaced. In the event of a case failure, the magazine and its contents may be ejected from the weapon. Therefore, do not place any body part or hard surface in proximity of the magazine. Also, do not hold the magazine or brace the weapon against the magazine while firing the weapon.
Q10. What kind of accuracy can I expect with the .17 HMR?
  Typically, the .17 HMR will shoot around 1.0 MOA or better at most practical distances. Obviously, shooter skill and wind will have a large effect on this as ranges extend. Please bear in mind that we do not provide an accuracy guarantee with this weapon.
Q11. To what range is the .17 HMR capable of shooting?
  We routinely shoot our .17 HMR rifles to 200 yards and will shoot out to 300 yards in calm conditions.
Q12. What types of lower receivers function well with the .17 HMR?
  The .17 HMR will function with any good-quality, mil-spec lower receiver. It is, by the nature of the conversion, sensitive to parts that are out of specification, specifically the alignment of the lower receiver extension, the extension itself, and the fire control group.
Q13. How do I install the conversion parts kit?
  The instruction manual included with your .17 HMR upper receiver or rifle fully explains the installation. A digital copy of the manual can be downloaded here. We have also produced a detailed instructional video for this procedure.
Q14. Will commercial-spec, collapsible receiver extensions work with the .17 HMR?
  Commercial-spec receiver extensions will work well as long as they are correctly manufactured. It has been our experience that certain extensions are internally too short and cannot be used (see the next question). Less frequently, these extensions are internally too long and are unsafe to use.
Q15. My recoil cassette does not fit. What is the problem?
  Typically, the main problem to date has been receiver extension tubes that are internally too short. The recoil cassette must be fitted with the aluminum buffer resting against the bolt. The original buffer and spring of the rifle has to be removed before fitting the recoil cassette.
Q16. I am using a fixed-length stock and full-length receiver extension. Why does the recoil cassette not fit normally?
  Fixed stocks with rifle-length receiver extensions require that a spacer be inserted into the stock before the recoil cassette. In some instances, specifically where receiver extensions are too short, it is not possible to correctly position the recoil cassette. In these cases, it is possible to fit the parts by shortening the spacer by the required amount. This is not always an easy or obvious solution and should only be attempted by a competent gunsmith. The extension spacer can be ordered as an upgrade to a .17 HMR upper receiver assembly or individually in the Online Store.
Q17. Are high-capacity or hunting magazines available for the .17 HMR?
  At this time, magazine capacity is restricted to 10 rounds, which creates a magazine that may be easily inserted and removed while shooting prone or from bench. A higher-capacity magazine currently is not part of the development plan. Any new .17 HMR parts will be displayed in the Online Store as soon as they are prepared for sale.
Q18. What is the muzzle thread size?
  The thread size is 1/2-28 TPI RH. This accommodates most .223 and similar muzzle devices.
Q19. What scopes do you recommend for the .17 HMR?
  Accuracy and range for this rifle typically will demand a variable magnification scope in the 4-16 range or similar. Equally, it works well with fixed magnification scopes such as x10. We find the mil dot reticle to be useful in shooting various ranges out to 300 yards. Despite the perceived low recoil, this rifle can be hard on an optic and higher-quality units should be used.
Q20. What handguard options do you offer for the .17 HMR?
  The .17 HMR comes standard with a non-vented, G10 fiberglass composite, free-float tubular handguard. As an upgrade, we offer the MK10 vented handguard, which includes threaded inserts for the mounting of optional three-inch rail sections. The monolithic railed upper receiver is also an option.
Q21. I want to change my handguard. What do I need to do?
  First, please be aware that we cannot provide direct instructions or support for the disassembly of our products. Any damage or issues that occur as a result of its disassembly are not covered by the warranty. Any disassembly or modifications to the product will void the product warranty. The standard handguard is screwed into the upper receiver in the same manner as a regular AR-15, free-floating handguard, and includes thread-locking adhesive to achieve a long, reliable life by preventing unwanted rotation of the handguard over time. Lastly, any modifications that an owner decides to make should be undertaken only by an experienced and competent gunsmith using the correct tools. Alexander Arms® does not perform customization services or produce custom parts for its products.
Q22. How often should I clean and lubricate my .17 HMR?
  The chamber will require cleaning and wiping at regular intervals (100 to 200 rounds) to ensure reliable operation during use.
Q23. Are replacement parts available? What are they?
  All of the small parts within the .17 HMR that may require replacement due to wear or damage are available as replacements. These parts are as follows. Additionally, we offer a heavy buffer for use with target-type or lightweight trigger groups. For items not posted to the Online Store, you may contact us by telephone.
Q24. I want to customize my .17 HMR rifle. What parts should not be modified?
  First, please be aware that we cannot provide direct instructions or support for the disassembly of our products. Any damage or issues that occur as a result of its disassembly are not covered by the warranty. Any disassembly or modifications to the product will void the product warranty. Modifications of the internal working mechanisms and parts should not be undertaken. This includes the complete bolt assembly, the recoil cassette, and changes to the fire control group outside of the approved target-type triggers. Pistol grips, stocks, and other peripheral components may be exchanged without negatively affecting the function of the rifle.
Q25. What cleaning solution should I use in my .17 HMR?
  For all normal conditions, the rifle should be operated in a lightly-lubricated condition after cleaning, using Break-Free® CLP or Mil-Tech. These lubricants will function in all but the coldest conditions and can be used down to -35°F, although application below 0°F requires the lubricant to be warmed. When applying Break-Free® CLP, always shake the bottle before use and clean and apply using a clean rag or cloth. The bolt, firing pin, firing pin retainer, ejector, and extractor assembly should be inspected for any damage before cleaning and lubrication. When applying lubricant, a light film implies that the surface is only just visibly oily while a heavy film implies the oil can be smeared with a finger. Break-Free® CLP and Mil-Tech lubricants can be obtained from all good gunsmiths. Tri-flow may be substituted for Break-Free® CLP or Mil-Tech in cold weather, if the action is sluggish.
Q26. How should the .17 HMR be cleaned and lubricated?
  Use a pull-through or a cleaning rod to pull a tight-fitting patch lubricated with Hoppes Elite Bore Gel through the bore of the barrel from the chamber to the muzzle. Repeat this procedure until the patch comes out clean. Clean the chamber with a brush, tear a small section of paper towel, wrap this around the brush, and use this to wipe the chamber dry. Lightly lubricate the magazine catch as required and wipe down the internal and external surfaces with a patch or rag and a few drops of Break-Free® CLP. Finish by applying a light film of lubricant to all surfaces of the receiver and barrel. Clean all surfaces of the bolt, carrier key, and trigger mechanism thoroughly with Break-Free® CLP. Apply a few drops of Break-Free® CLP to the inside of the tube that houses the recoil spring and buffer. We have also developed an informational video to explain these processes.
Q27. What is the recommended cleaning frequency for the .17 HMR?
  You should clean your rifle every 100 to 200 rounds.
Q28. Can I use a polymer or cast lower receiver?
  No, you should not use polymer or cast lower receivers. The rifle is designed to use either a forged or billet aluminum receiver, typically with mil-spec tolerances. Polymer receivers will have problems with respect to tolerances and strength.
Q29. Does the .17 HMR bolt lock open?
  No, the .17 HMR AR-15 weapon system does not feature the ability to lock the bolt open after the last round is fired. The design of the weapon prevents the inclusion of this feature. It cannot be retrofitted or added.