***Use NO OIL internally in the weight.***
TUNING:
TL;DR: As of 8/25/2026, our minimum recommended barrel length is now 7″, which will run without any weight tuning when using our 22lr ammo recommended FRT.
12″ and higher barrel lengths will now run a much larger variety of ammo types, including some types of subs and standard velocity without any additional tuning.
Below 7″ in length requires extensive knowledge of the platform and how ammo types influence cycling plus extra patience to tune and test ammo types. Use a BoreBuddy 22LR Certified FRT trigger system for best results. Please reference our FRT trigger guide.
We highly recommend starting with a 12″ or longer dedicated upper with the add on bundle for your trigger type selected. Builds with a certified trigger system (ARC-FIRE or Atrius Selektor with a Rave 140 trigger) in the lower do not require any tuning in the vast majority of builds.
If your barrel is 7″ or longer, using a steel weight and steel inserts and recommended ammunition generally results in immediate function with one of our uppers. FRT-Ready Uppers come set to this tune point.
If your barrel is less than 7″, tuning will be more time consuming and generally requires ammunition to be carefully selected.
Generally we recommend the following as a starting point, broken down by barrel length and ammo type:
12″ or longer barrel (tuning difficulty: EASY)
Using good quality ammo and a reduced power hammer spring with a Super Strike firing pin is recommended.
Ammo Types we’ve had good luck with:
High velocity ammo (40gr Mini Mags recommended): Stainless adjustable using steel internal weights
Standard velocity ammo: Stainless adjustable using steel internal weights
Subsonic ammo (Cascade 50gr recommended): Stainless adjustable using steel internal weights
7″ barrel (tuning difficulty: Easy)
High velocity ammo: Stainless adjustable using steel internal weights
Using a reduced power hammer spring with a Super Strike firing pin is recommended.
Ammo Types we’ve had good luck with:
Cycling problems may occur with 7″ barrel and subsonic or SV ammo. Short barrels result in many HV ammo types being subsonic, so there is no reason to use subsonic ammo)
4.9″ barrel (tuning difficulty: moderate)
High velocity ammo: Start high (Steel with steel weights) and work down one step at a time until function is achieved.
Using good quality ammo and a reduced power hammer spring with a Super Strike firing pin is essential.
Ammo Types we’ve had good luck with:
Cascade 1500 (BEST CHOICE, generally no tuning required)
Cascade 40gr HV (Good Choice, little to no tuning)
CCI Mini Mag 40gr (Requires more tuning)
Cycling problems may occur with 4.9″ barrel and subsonic or SV ammo. Short barrels result in many HV ammo types being subsonic, so there is no reason to use subsonic ammo)
Tuning the Bolt Weight
SUPPRESSORS AND TUNING
Suppressors do add a marginal amount of cycling force, especially as the barrels get shorter. Expect very little difference in tune point at 12″ or more, and a marginal difference at 4.9″ and 7″. A slight rate of fire increase can be seen with a suppressor.
Generally we recommend tuning unsuppressed and then when suppressed the system will not need any changes to run. Builds using short barrels sometimes benefit from tuning with a suppressor due to the narrower tuning window for short barreled builds.
POLISHING FOR BETTER FUCNTION
(ESPECAILLY FOR SHORT BARRELS OR SUBSONIC USE)
Polish the hammer face, bolt reset surface and feed ramp/chamber for best function in FRT mode.
TROUBLESHOOTING:
DEAD TRIGGERS and Light Strikes:
Dead triggers and light strikes are the most common malfunction in FRT mode. If you get a couple shots off and then a dead trigger with a light strike, this is typically short stroking. Short stroking occurs when the bolt does not travel rearward far enough to reset the hammer, and hammer follow occurs. In semi-auto mode, this can result in multiple shots being fired as the hammer rides the bolt forward and can set off a primer during hammer follow.
Solutions (generally in order of easiest/cheapest to hardest/most expensive:
- Reduce bolt weight: Too much weight will cause short stroking. Drop back to a lighter set point until perfect function is achieved in semi-auto, then test FRT. Drop back more if necessary
- Reduce Trigger pressure: The harder you squeeze, the more force is required to bump a trigger reset. Squeeze lightly or farther towards the top of the trigger.
- Hotter ammo: If the above fails, step up in ammo quality and velocity. Doing so will move the proper weight set point up and allow function. 40gr Mini Mags are the ammo we use 99% of the time.
- Longer barrel: Short barrels reduce the velocity of all ammo. Mini mags run around 1250fps from a 12″ or longer barrel, but generally run around 1080fps from a 7″ and 950fps from a 4.9″. If your barrel is below 12″, consider a longer barrel, or go back to ammo and try a hyper velocity (1400fps or more) load such as CCI Stingers, CCI Velocitors, Aguila Interceptors, etc.)
- Use a reduced power hammer spring and super strike pin (applicable to super safety and ARC-FIRE). Links below for both.
FAILURE TO EXTRACT SPENT CASES OR STOVEPIPE OR DEATH JAMS:
This is generally caused by short stroking as well. See “Dead Triggers” for solutions.
Certified triggers do not require timing adjustment.
Rarebreed Style timing adjustment: