I must admit I have a fascination with the 10mm auto cartridge.  First, it has cool ballistics. Second, it can be found in a number of semiauto pistol platforms including my favorite 1911/2011 platform.  Third, I’ve wanted one since Miami Vice in the 1980s 🙂  Honestly, it is the first two reasons – the ballistics of the 10mm are pretty amazing and I wanted something in a 1911/2011 style pistol.

While some folks were reading the blog post, they pointed out a common misconception that the 10mm and .41 magnum are similar when, in fact, they are not.  I went over to gunnersden.com and grabbed some data from their ballistics table for pistol cartridges to show the 10mm compared to the .40, .41 magnum and .45 ACP.

Over the past year, Scott Igert, of Modern Antique Firearms, has helped me track down two 10mm pistols that I want to share with you including the Rock Island 52000 6″ Pro Match Ultra (some call it the “Big Rock”) and the Dan Wesson 6″ Bruin.  In this post, I’ll focus on the Big Rock.

My first choice was a STI Perfect 10 but they had stopped the 10mm model I wanted in 2016.  I wasn’t too keen in buying an out of production model so I continued digging around and wound up reading about the Big Rock. Now I realize you can’t compare STI and RIA pistols so let’s just shelf that right up front.  What did intrigue me about the Big Rock were very good reviews and a very affordable price point for a true double stack 16+1 10mm pistol with a 6″ match barrel.

In case you aren’t that familiar with RIA pistols, they are made by Armscor of the Philippines. Armscor is the biggest producer of 1911 style pistols in the world including making pistols for Auto-Ordnance, High Standard and even the STI Spartan. These folks know their way around a 1911 and the Philippines has a big time gun culture either equal to  the US or only second to the US.

While their manufacturing has traditionally been in the Philippines, my understanding is that some production may be moving to the US, but the Big Rock I bought was made in the Philippines by gunsmiths in their Medallion custom shop.  The Medallion gunsmiths hand select and assemble each pistol resulting in a pretty solid pistol with an excellent prive:value combination.

Now, value really depends on the customer – either me or you.  So let me tell you key features that mattered to me:

• 4140 Ordnance Steel that is CNC machined – folks, read up on the first batches of 10mm pistols including the Deltas. They would shoot themselves loose.  Metallurgy has come a long way.  I read good reports of the fitment and functioning before I bought the pistol and mine arrived snugly assembled. I loathe loose slides and barrels – the Big Rock is solid.
• 2.5 pounds unloaded and 2.9 pounds loaded – I wanted it to soak up the recoil of the pistol plus heavier pistols always work in my favor when it comes to dampening my tremor.
• 16+1 rounds – because you don’t buy toilet paper a square at a time 🙂  Seriously, I prefer more ammo and I like thicker grips. Years ago I had a Desert Eagle .44 Mk.V and loved the feel. This is the same way.  I wear XL-sized gloves due to big palms and relatively short fingers. I really like the feel of the 2011 family. In the event I were to ever use this pistol in a self-defense situation, I would prefer the extra rounds.
• On a related note, the pistol has G11 grip panels that aren’t overly aggressive cut. G11 is basically a family of epoxy refinforced fiberglass laminates. They are strong, durable and aren’t going to split, warp, or wear like wood.  Havin worked with it on knives, I knew this would be a solid route to go. My first preference in a 1911 single stack are the rubber Hogue grips but he Big Rock’s grip would be too big for me.  I didn’t even try changing the G11 panels out once I received it. The big frame and these G11 panels work well together,
• 6″ bull barrel with 6 grooves, a 1:16 twist and integral feed ramp – this barrel will be more accurate than I ever will be. I liked the fact it did not use a bushing, that the feed ramp was there and it had the right twist rate for 10mm.  As an aside, I went with the 6″ barrel because this will be a range or hunting pistol. If I wanted something for carry or duty, I would have gone with the RIA Tac Ultra FS (Full Size). RIA also makes a Tac Ultra MS (Mid-Size) with a 4.25″ barrel.  You’ll notice I didn’t mention Glock or SIG and that’s just because I wanted a 1911/2011.
• Adjustable trigger pull from 4-6 pounds and adjustable over travel – I am a trigger snob. The Big Rock’s trigger is pretty decent but the trigger on my Dan Wesson Bruin is fantastic. When I have time, I want to dial the pull down some. The over travel is set right I just wish it broke a bit lighter, It’s a tad gritty but I expect that to wear in and smooth out as the parts get to know each other.
• Fiber optic front sight and adjustable LPA-TRT rear sight – as I get older, I find simplicity more and more appealing. The problem with optics is that they break, the point of impact shifts, batteries die, you have to fumble to turn them on in a high-stress situation, etc. I wanted good reliable sights. Now I will tell you the front fiber optic sight was too dark for me out of the box and I had Scott work his magic on upgrading the sights but that’s a story for another time.
• Picatinny Rail – on pistols that I may use for self defense, I like to mount a true weapon light and laser. The Big Rock has a nice long steel rail to do whatever you want. I mounted a Streamlight TLR-2 HL G, which is a reliable 800 lumen light with an integral green laser.  I’ll tell you more about that in a future post.
• Magazine funnel – when I am in a rush, I want a nice big magazine well to shove the next mag into.  I find them more forgiving and faster than having to slam a magazine into a tiny opening.The Big Rock comes with a nice big funnel already installed
• Parkerized finish – I do manganese parkerizing and like the dull black look. Keep it oiled and you are good to go. Note, Parkerizing isn’t a rust proofing – it modifies the surface layer of steel allowing for other things to get a good hold. For example, parkerizing and grease, parkerizing and cosmoline or parkerizing and then a weapons finish such as Molyresin.

Now you notice I didn’t list the dimensions as important considerations and that was because I didn’t really care how long (9.75″), wide (1.41″) or tall (5.5″) the pistol was. If these are important to you, great – they just weren’t important to me when I bought this pistol.

In buying this pistol, it was not easy to find and required some serious online hunting at Able, Buds, etc.  Honestly, the biggest problem with the Big Rock is finding a dealer that has it in stock. Scott was looking for me and I also had a number of automated searches set up on GunBroker and finally one showed up for sale by Elk County Arms & Ammo of St. Mary’s,PA, for $1,2339.49 out the door. These folks were professional and a delight to deal with. They promptly processed Scott’s FFL information and shipped the pistol just a few days later.  If you see something listed by them on Gunbroker you’ll notice a ton of positive reviews and one of them is mine!

To break the pistol in, I bought 500 rounds of S&B 180 grain FMJ and then Underwood 155gr XTP and 180gr bonded jacketed HP ammo. I also bought three more magazines direct from Armscor’s website.  I had to call them and confirm the magazine so here’s the link if you want to do the same.

So, the pistol comes seriously covered in oil. When I was taking it out of the bag,I couldn’t help but think “Wow – this is awesome!”  Getting ready to go to the range, I field stripped it, cleaned the barrel and lubed everything just like I would any other 1911 with the exception that you have to unscrew the guide rod and there is no bushing to deal with.

March 2024: I bought a second 52000 Big Rock and carefully documented why cleaning, lubrication and getting a jump start on breaking the pistol in are so critical for a stress-free first range trip. The pistols are not ready to go right out of the box. Click here.

We set up the target and the pistol functioned great with the S&B 180gr FMJ rounds. With the Underwood, things got ugly fast. Literally every 3rd to 5th round the pistol would fail to feed (ejection was fine but not feeding). This happened regardless of magazine or Underwood load.

So, I took it home and contacted Underwood and they questioned the recoil spring. I bought  Wolff 22# spring and started monkeying around with stripping the frame further and got the mainspring and trigger jammed – this was totally my fault and I decided to have Scott send it back to RIA to fix both my mistake and to check about feeding HP ammo. I was fully prepared to pay them for my mistake but they took care of everything in about 2-3 weeks and sent the pistol back to Scott noting that they could find nothing wrong with the pistol that would affect its ability to handle JHP ammo.

Now Scott is a good friend of mine and has been around guns and reloading his whole life plus is a career police officer so he is very pargmatic about everything.  Scott was also intrigued about what was going on with the Big Rock and took a closer look at the Underwood Ammo. He noticed there was quite a lip at the top of the case and that almost all the Underwood ejected cases had a scrape/gouge created during feeding, He then speculated that the match chamber of the Big Rock probably needed a more of a taper whereas the Underwood ammo was all straight. The next photo shows the scrape and gouge in one example Underwood round:

Scott took home a box of the Underwood ammo and put a slight taper on all and I met him the next day with my pistol – they all fed. We also took a box of SIG V-Crown 180gr JHPs which came from SIG with a visible taper and they fed just fine as well.  In the next photo, the Underwood round is on the left and the SIG is on the right – you can see the difference!

I contacted Underwood and told them about my findings and was a bit disappointed that they blamed the pistol and did nothing to compensate me for all the hassle – heck, I would have been happy to get a couple of more boxes of ammo from them. By the way, my 10mm Bruin feeds the Underwood ammo no problem so the issue is with that particular pistol and ammo combination.  Underwood did say they would take my findings into consideration and potentially change their production method but it did not sound certain at all.  Bottom line, I will not be ordering more Underwood ammo for this pistol.

So, a very valuable lesson was reinforced again — it pays to test ammo and find what is reliable in your pistol.  As the saying goes, practice, practice, practice.  Scott is going to take the balance of my 500 rounds of Underwood ammo and put a taper on them so I am not out my investment plus make me some ammo.  I’m also going to finally get into reloading myself based on his recommendations plus will contact some of the other ammo companies to find out who else tapers their ammo just in case.

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April 2018 Update:  I did resolve this reliability problem with Underwood Ammo in the Big Rock.  Click here to learn how and it is super easy.

7/9/2021 Update: We make and sell magazines for the double stack 10mm and .40 S&W RIA pistols Click here for the listing in our store.

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The Big Rock is a very cool pistol and I am impressed. Their customer service also was a very pleasant surprise — I would have been more impressed if they had resolved the problem.  My problems were just with the Underwood ammo but others do not report this problem so it was a case where the pistol and ammo didn’t work together and this does happen.   A ton of people read this post so I want to be candid with you  so you can learn from what I experienced.  I’ve sold the pistol as it was interesting for a time but decided to move on to other projects. With that said, I’d recommend it if you want a big double stack 2011-style 10mm.

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