Keltec RDB Accuracy Testing

Greetings Programs! This is thread I started on AR15.com but I felt it would also be better here.

This is not a supplemental to LAZYS RDB Rifle Log. That is more an adventure with the current production Keltec RDB's.
and is worth the read if you wanting to see him put the gun through its paces and maybe what ammo may work best in your 1:7 Twist RDB.

Mine is a bit different.
I have a early, Preproduction1:9 twist rifle and have been on the look out for making this rifle shoot tiny groups. This is the rifle some of the very first written and video reviews are on.
Typically anything I shoot in my RDB is also followed up by my Stag Arms 1:9 twist AR15..Just to compare.

Also @shenendoah_rifleman and mcantu asked to see what I could do with 10 round groups in my RDB..

Folks have tried to point to other bullpups being "The Most Accurate Bullpup" on the market..My experience says "it really depends on what ammo your shooting."
Its also my belief that you can get just about any modern bullpup to shoot 1.5moa or less once you get away from the bulk military stuff.

**Some History**
I actually started looking at ammo loaded with 50gr projectiles after seeing this gentleman's extensive ammo testing .. The range is 1.3moa - 3.4moa 5 shot groups
. I don't remember where on KTOG I found it..so I cant put his name here for the credit..(so if your seeing this My Apologies)... Lazys 1/28/2024 Rdb info is starting to look more like this.

The Rifle


Having found a round I can afford to shoot and still find (very important)..

- The unmeasured groups are from a Tavor Sar and Springfield Vhs2 (Hellion) with the same ammunition.


My RDB is capable of slightly over 1moa when averaging (2)5 shot groups (with and without my suppressor attached).
That's not to say I haven't tried other ammunition. Ive shot alot of different brands and bullet weights over the years through the RDB.I also got better at shooting for groups. This is the test where I first figured out which load I should be buying..
I tried Black Hills 223 50gr..Some PMC 62 XTAC LAP and what was then labeled Fiocchi Extrema..later renamed Fiocchi Field
2.28moa 50gr Black Hills 223
2.77moa 62gr PMC Xtac (which..is pretty typical. I have a 9 shot group that's barely bigger than this)..
0.99moa 50gr Fiocchi Extrema
I shot those only with a 3.5x Prism (which makes them 223 sized holes near impossible to see at 100yards)

Without further ado..

Rifle
RDB17 Circa 2014 1:9 Twist BBL
Cobolt Kinetics 5.56 HxWrks Compensator
LuckyIrishman Rhino Handguard
Aluminum lower Pic Rail.Cut match the length of the Rhino handguard (mostly to hide the UGLY Gap between the handguard and the trigger guard..
GunWraps Vinyl Wrap in Kryptek Raid
Sig MSR 1-6
..Bench Block...
Aero Precision Ultralight SPR Scope Mount-1.5"

Here be my 10shot groups with my RDB.

I show both groups and took more time with groupd#2 vs group#1..So the Average is 1.5moa between both groups

These were shot without the suppressor attached.(I.. uh..got it carbon locked onto my 308Mdrx for the same range session )

Ammo cost
While not the cheapest ammo at 0.63cpr (12.60 for 20).. its  slightly more expensive  than the current prices for Winchester White box m193 55gr @ 0.49cpr (9.99 for 20)
And
Pmc Xtac 55gr @0.52cpr (10.49 for 20)
(Circa 2024)
But much more affordable than
69gr Fed Gold medal @1.29cpr or 25.99 a box
Nosler Match 69 gr @1.24cpr or  24.99 a box
(I use these in my 1:7 twist guns)


I think If I pay better attention I might be able to shrink my average group size (between 2 groups) to around 1.2moa just looking at the round that broke the #6 (which would have been a 1.2moa group but for that).
I also wonder if the suppressor would shrink that group to 1moa average..Ill find out next time.

is about what my Stag15 (a 1:9 Twist AR15 does with the same ammo)
For those curious what that setup looked like,
Rifle
Stag Arms Ar15 16" 1:9 Twist BBL
Phase 5 Fatman Muzzle brake
Atlas S-one M-lok handgaurd.
BCM Gunfighter Grip .
Timney Competition Trigger.
Spikes Tactical ST-T2 buffer.
Arken 1-8x24 FFP scope
Aero Precision Ultralight SPR Scope Mount-1.5"
Magpul UBR 2.0.
..Bench Block...

This is amazing to digest.

When I get home and 3gun the Tavor this is something I've been quite curious about. Granted I have a 5x magnifier. But the romeo5 is a 2 moa dot.