David Tubb’s 33XC

King of 1 Mile in France 2020

Winning Cartridge

David tubb's 33XC

33XC powered 300 Grain Berger bullet hitting the dirt at 2miles sending that magical splash every spotter hopes for! Thanks to Mauro Del Mastro for this fantastic shot!

In this article we shall discover:

  1. What’s this 33XC (eXtra Capacity) cartridge everyone is bragging about?
  2. Why 33XC over 375 Cheytac?
  3. 33XC ballistics
  4. What’s it like to spot for the 33XC?
  5. What does a winning 33XC rifle look like?
  6. Chat with Winner of Ko1m in Caylus, France 2020- Benjamin Gineste
  7. Head-to-head with Mauro Del Mastro who is on his 2nd 33XC barrel!
  8. Head-to-head with 33XC creater David Tubb
  9. Chat with Robin Epps who just built a 33XC heavy class rifle

Disclaimer: The opinions shown in this article reflect that of the individuals interviewed. Any load data shown here is not to be replicated without working up a load in your rifle following standard loading procedures. There are no short cuts!

Italy Shoot 33XC to 2100 Meters – Cold Shoot EXLRS Italia

Find out more about this Cold Shoot Italia ELR calendar event in Europe held in Winter and Summer where we shall be running the DTA in 33XC.

Cold Shoot ELR shooting
Setting up the rifles for a 2000m+ Shot at this beautiful range in Northern Italy

What’s this 33XC (eXtra Capacity) cartridge everyone is bragging about?

33XC by David Tubb
33XC by David Tubb, holds up to 130grains of powder!


Read the full report of the compact Desert Tech SRSA2 in 33XC

Let’s find out more about the 33XC the winning cartridge at King of 1 Mile in France. Some months ago we wrote an article about the 37XC. Now we take a look at its necked down version to .338 which David Tubb has created.

338 Lapua cutting edge bullet

It’s a 338 Lapua on steroids without the hassle involved in improving the 338LM case. It uses the same bolt face (0.580”) as the 338LM so no further expenses except changing the barrel out and new set of dies and brass ($2000?). No wonder the 33XC is fast becoming the cartridge of choice. If you already have a stack of 300 Bergers as many 338 Lapua shooters stock up, you don’t have to change anything.

Got a 338 Lapua? Keep it – Just change the barrel and you have 33XC!

voere 338 Lapua

Load testing a few 338Lapua cutting edge bullets here in Trapani, Sicily where the nextis gonna be held early 2021!

From David Tubb’s document “The 33XC (eXtra Capacity) has (139 gr of H2O capacity) while approaching 130 grains of useable powder capacity yet leaving the .393” neck unfilled (for bullet seating as it should be) – depending on the powder density and drop tube length.”

Why 33XC over 375 Cheytac?

37xc 375CT cartridge comparison

Left to right: 338 Lapua (empty)- 33XC Warner 256gr Flatline – 33XC head – 37XC Warner 361gr Flatline – 375 Cheytac (empty) Note – the XC case length VS. the 375 Cheytac. Pic. courtesy of Vestals custom rifles.

Tubb reports, “the .375 Cheytac uses over 30 grains more powder to get another 100 feet per second. Cheytac issues are as follows:

  1. Need to buy a new, larger reloading press.
  2. Need to buy custom dies, which are overpriced, and they still may not work as you would like them to.
  3. Need to buy a larger action diameter, so figure a new gun is in order”

How much flatter is a 33XC wind-wise compared to your current 338 Lapua?

Just deduct 1 MOA from your windage at 1000m, 2 MOA at 1600m, 3 MOA at 2000m and 2.25MOA at 2 miles😊😊😊 The table below compares a few ELR cartridges from 300Norma, 338 Lapua, 33XC, 37XC, 41 XC and the mighty 416 Barrett with popular loads maxed out for ELR using long barrels. (Again work up loads in your rifle using standard safety procedures and best practices.)

33XC 37XC 41XC cartridges
33XC 37XC 41XC cartridges

Why do I speak of wind drift numbers? Because once you dial your elevation, you’re fine but as we’ve seen at Ko1M in France, it’s the windage that kills your points hitting half a plate out whereas a flatter wind-shooting cartridge would have meant a hit! At this level, everything matters. More energy down range kicks up more dust making life easier for your spotter as well.

david tubb 33xc ballistics

Notice how using the same parent cartridge and changing bullets/calibre from .338 to 0.375 (37XC), the wind deflection drops considerably burning the same amount of powder [better bullet, higher BC]. The only difference here being the bullet costs from shooting conventional copper jacketed 300 Bergers to shooting monolithic solids in 37XC and increasing bullet weight from 300grain to 400grains.

What’s it like to spot for this cartridge?

David tubb's 33XC

Thanks to Mauro del Mastro for sharing this impact moment of the 300 berger with us!

There is a beautiful relation between the ballistics you see on paper and the real-world performance that you see on the range. Very few things can make you appreciate a cartridge as when you see it unleashed on a rifle range. This was the case for us when witnessing the 33XC at work. David Tubb had reported how effective this cartridge is, he put a lot of information out there in his facebook group which is amazingly helpful. Other shooters like Paul Philips and Mauro del Mastro attested to the 33XC awesome ballistics but as they say, “seeing is believing”.

Spotting remains a critical skill to put rounds on steel plates. The spotter has the central role to read wind for you, is hopefully the more experienced of the team and can detect impacts and follow the bullet trace with the ability to quickly provide adjustments and guide the shooter on where to send the next round as he is watching the wind. The 33XC makes your life as a spotter a bit easier.

Better spotting scopes also make your life easier. Here are some examples we have made use of and love.

swarovski ATS 65 with reticle
swarovski ATS 65 with MOA reticle
Swarovski btx 95mm
Swarovski btx 95mm

Kowa highlander 82mm spotter

Kowa High Landers 82mm Big Eyes – Binocular spotting scope

We were just about to start filming through the Kowa Highlanders 82mm spotter when I captured sight of this very evident trace and a bullet slamming the 900m target when I was like WTF was that, it can’t be 338 Lapua! Below you can see his impacts from 1250m to 1340m during the qualifying stage.

Watch Benjamin Gineste behind the 33XC at 1250m at the qualifying stage of King of 1 Mile in Caylus France, 2-4 Oct, 2020

I’ve spotted often for 338LM shooters to know that a 338 Lapua trace is not quite as flat. My shooting buddy Bill and Godfrey shoot 338LMs every time we do a trip together. In my broken French I asked Romain next to me, what’s this guy shooting?

He whispered trente trois XC – 33XC! Ok – now we’re speaking 33XC and driven by a great shooter, Benjamin Gineste a member of the French ‘chasseurs’ regiment – deadly combination guided by his wife Alix, an experienced spotter who has been shooting with her husband over 10 years. Kind of reminds me of Mark and Sam after work. Those 300 grain bergers made their way towards the target and came down like the hammer of Thor! I can see why David Tubb and Mauro del Mastro were quite impressed with the 33XC performance.

david tubb 33XC rifle setup

Mauro, an Italian living in the US with a fantastic passion for ELR shooting did a few trials with it at 2 miles with success shooting out in the desert. He reports that he can get 3250ft/s in a 32-inch barrel with a 300 grain Berger in a 1.9 twist using 8133 IMR however he’s keeping it at 3000ft/s. This will also save him a few trips to the gunsmith yearly. 😊 (read the interview with him further down)

How barrel hungry is it?

As hungry as other high-performance competition only cartridges. I reached out to three persons to learn more about this, Benjamin Gineste who won the ko1M, gunsmith Ryan Pierce and 33XC cartridge creator David Tubb.

Gineste 👑: I have been using this caliber for two and a half months and today my barrel must have 200 shots.

The lifespan of the barrel is extremely short. between 500 and 1000 shots maximum depending on the powder used.

Rod: That’s about a year to two years of competition shooting. Pas mal as the French would say considering it can be the ticket to secure yourself a few titles. IF Benjamin continues in this manner, he may be crowned king another 3 times before the barrel is scrapped. You can’t race formula one and be bothered about your tires right? Same here.

What’s recoil like on the 33XC?

33XC heavy gun
33XC heavy gun 38lbs rig by Robin Epps

Well in a heavy gun quite nice, checkout this video I came across of Robin’s rifle. His weights 38lbs, 19kgs. It wouldn’t make it under the new Ko1m Rules but it would make it for the Ko2M.


What does it bring to the table for hunters?

Given that you can build one on your existing 338 Lapua mag action and if you’re happy to single feed your rounds, you can build a 33XC for your hunting needs maybe using one of the newer carbon wrapped barrels. This would appeal to hunters who are hunting out west or in mountainous terrain where wind bucking qualities of this cartridge may come to their aid. Even with shorter barrels, 3000ft/s with a 300 Berger is no slouch and will bring down anything you may encounter with 1 shot. For more info on this I suggest you checkout www.longrangehunting.com

Will 33XC make you a winner at your next national or international tournament?

That’s the million dollar question right? We witnessed hits and misses with the 33XC. I saw an identical 33XC rifle being shot by another competitor during the ko1m in Caylus that qualified for the finals yet still had a few misses on the 1415m target.

33XC shooter Joachim Son Forget  at Ko1M in Caylus France, 2-4 October 2020 during the Finals. He had a few misses with tricky twitch winds there.

It’s not magic and wind will still cast it’s spell on your shot but it will effect you less. Notice his elevation was off for the first 3 shots but he was there for windage! You also have to master the added kick from the mule going off. Having a great muzzle break will help as well as a heavy barrel but watch your weight, waistlines matter in shooting too 😉

I watched Gilles Combaz shoot a 300RUM at all the targets out to 1 mile during the final of Ko1m with a factory sako TRG42 barrelled with a custom barrel. He hammered those metal plates like a boss. Notice how fast he’s shooting and watch the trees further on behind the tank, it’s gusting down there. on the second target, his shooting is much better. fast forward to 03:40

Rifle build and weight limits

With the new ko1m restrictions in weight set at 25lbs (11.33kg) for the entire rifle and bipod as well as limitations on Fclass like bipods, shooting a bigger round will take some work on your technique as you are made to absorb more recoil after the muzzle break has done it’s bit to tame those 120ish grain of powder going off!

What does a winning 33XC rifle look like?

Well, what’s better than asking the winner of Ko1m in Caylus, France 2020?

We asked Benjamin about his rifle, curious as we were to learn more about the winning bang stick.

Rod: What about your rifle, what are the specs on it?

Gineste 👑: AHAH! it is the most wonderful of guns.

This is a Precision Custom GS from my English friends Gary Costello and Stuart.

He is by far my best gun. it’s the perfect combo between optimal performance / size / weight. (someone found the perfect balance!)

To go into detail it is:

  • BAT M action
  • Barrel Benchmark 34 inches
  • Terminator muzzle brake
  • Triggerthec relaxation
  • Tier one rings
  • Zero Compromise Optic 5-27X56 bezel
  • LRA bubble level
  • Sandro Caroselli anti-mirage tape

Head-to-head with Mauro Del Mastro, 33XC Shooter on 2nd barrel…

33XC mauro del mastro
33XC Mauro del Mastro’s setup using Charlie Tarac there shooting somewhere out in the Nevada desert.

Rod: How long have you been running the 33xc and how many rounds have you put through your barrel?

Mauro: I started shooting the 33XC a year and a half ago and so far, I have 500 rounds through the second barrel. It looks fine and normal expected erosion is taking place but I keep the bullets velocity at 3015 FPS period +/-

Rod: How many firings can the brass take if you’re running it at 3200fts?

Mauro: At 3200 FPS erosion is more aggressive and my first barrel died around 900 rounds. At 3000 FPS is where the magic really happens for the 300 gr Berger on this particular rifle.

I’m reloading the same case for 12 times so far and the primer pocket have lost a bit of grip but no leak and still safe. I do anneal the brass every shot. (Rod: Wow 12x that’s something)

I reload on site in my car for all the testing which saves time & money and you get to shoot very fresh ammo. Once I get what I want, I reload at home a day earlier.

33XC reloading setup in car

Rod: Do you manage to see impacts at 2 miles and what sort of terrain do you shoot in Mauro?

David tubb's 33XC

Mauro: At two miles I’m able to see the bullet impacts ( sand or plate) through a decent spotting scope but also the rifle scope (Nightforce 5.5-22×56)

So far up to 2.5 miles spotting was easy but I live in a very sandy desert and I’m one man show. Hit on a plate will be a bit harder to see but I still manage to spot.

Rod: How much elevation and windage do you need at 2 miles with this cartridge on average where you shoot?

David tubb 33XC ballistics 2 miles

Mauro: Elevation at 2 miles vary from 193 to 200ish MOA depending on the temperature at an elevation of 2800 feet with the 300 Berger 3015FPS and of course solids will need about 8-10 Moa less, I shoot the BadLand 265 gr. at the same speed but different powder.

Rod: What powder do you suggest?

Mauro: The powders I use are the IMR 8133 which is my favorite ever is a very stable powder, it keeps the barrel free of copper and easy to clean.  No matter the outside temp velocity stays the same as far you reload just before the practice day. The other powder is the RL26  which is my plan B in case the 8133 is not available.

Wind on an average day is around 1 or 2 MPH (Usual around up here until 9 am) needs around 8 MOA of correction and 7 seconds Time Of Flight!!

Rod: Do you use a Charlie Tarac, Ivey, MOAB or Eratac mount to get you out there?

david tubb 33XC rifle setup

Mauro: I use a Charlie Tarac set at 178 MOA and about 25 MOA on the scope.

The Charlie eliminates the need of high cheek piece which is needed if you run any adjustable picatinny rail or rings. I have been there and realized that those systems create a lot of unnecessary additions. With Charlie Tarac nothing changes, everything stays the same but the amount of MOA now available.

Rod: Thanks Mauro molto piacere!

Looking to take the 33XC further out?


We took the awesome 33XC F1 cartridge to Tuscany Italy to run the 33XC to 2100m. After 3500km round trip, we had some very good quality time with this scope which we had been eyeing for along while before we pulled the trigger on it. Read the full March Genesis review here.

March Genesis

March Genesis 6-60×56 Scope looking at a long distance building while setting up our trigger cam to it.

Head-to-Head with David Tubb – Creator of the 33XC Cartridge

David Tub 33XC

Rod: How long have you been running the 33xc?

David Tubb: I have been running the 33XC a little over 2.5 years.  In December of 2018 the 33XC won the ELR cold bore record recognized by the Fifty Caliber Shooters Association with 3 shots and 3 hits at 2200 yard.  link attached here   https://youtu.be/xTYETDqxkC8

Rod: How many rounds have you put through your barrels on average before scrapping them?

David: If using lead core bullets through a 33XC with 3 lapping TMS bullets every 200- 250 rounds and controlling the rate of fire,  I average 1100-1200 rounds per 33XC barrel.  The TMS bullets really help extend the barrel life.  Shooting the same diameter turned solids will give a shorter barrel life.

Link to TMS bullets: http://www.davidtubb.com/tms-338?search=338

Rod: Have you looked through the barrel with a borescope since, what’s it like?

borescope bartlein barrel in 300 Norma

Above, my 300 Norma Mag Bartlein barrel after 200 rounds with 215 berger at 3250ft/s!

David: I always look at the barrel after shooting 200 rounds.  At this point I can see the hint of stress cracking. I’ll typically shoot 3 TMS bullets through the barrel at this point in time and then continue shooting. I will check the barrel again in another 150-200 rounds and continue this process.

Rod: How many firings can the Peterson brass take if you’re running it at 3200fts? We want a 33xc to perform at its peak.

David: I shoot my brass with lead core bullets at 3150 fps and after 6 or more firings I am getting a new barrel so I then get new brass.  I have yet to have a Peterson case fail ( by that I mean I have yet to have a web separation on a piece of brass). I aggressively small base and full length resize the fired brass every time.

Rod: Do you manage to see impacts at 2 miles with 300gr Bergers and what sort of terrain do you shoot on David?

I use KOWA highlanders and I shoot under good conditions to see impacts.  The misses are typically always easy to see if there is backstop behind the target where dust can be kicked up. I typically have terrain oriented backstops because the land is not flat where I live. Impacts are typically harder to see than the misses.

Rod: How much elevation and windage do you need at 2 miles with this cartridge on average where you shoot?

David: To shoot 2 miles with the 33XC I need approximately 50 mils of elevation

Rod: Do you use a Charlie Tarac, Ivey Mount, MOAB or Eratac mount to get you out there?

charlie tarac Tacoma HQ
Charlie Tarac Periscope System adds Elevation to your Rifle scope optically. Pic courtesy of SSD in Netherlands

David: I would use a Charlie Tarac unit to get the 33XC past 3000 yards. If you’re in Europe, speak to SSD in the Netherlands for a Charlie Tarac, Harry is the man there.

Rod: Do you have any advice for those wanting to run a 33XC?

David: Advice is buy a .338 TMS kit from superior shooting systems and shoot 3 TMS bullets through your barrel every 200 rounds to extend your barrel life.

Our resize die and seating die will accommodate the 33XC/37XC and 41XC and anyone call load all of these calibers on a standard reloading press.

I would also suggest reading the 33XC/37XC/41XC writeup found under the articles section of davidtubb.com to avoid confusion and to learn from what I have experimented with that works well for the 33XC.  I also would encourage those interested in the caliber to join the TUBB original 6XC and 33XC/37XC/41XC facebook page as we are always posting helpful advice on the XC calibers.

Rod: What powder do you suggest?

I prefer H50BMG because it’s temperature stable and has a slow burn rate and works optimally for 300 grain bullets with 33XC.  Others have had success using IMR 8133 with the 33XC.  Those who live in Europe have started to use N570 but I have not tried it myself.

Rod: Note that Benjamin Gineste also suggested the VV 20N29 Powder. We are still to try this powder in our rifle build.

Head-to-Head with Robin Epps who finished a 33XC build recently

33XC heavy gun

Rod: Big gun there Robin, how heavy is your rifle?
I built it at 38lbs with the T5 terminator brake!

Rod: Beautiful gun Robin! Are you using it for ko2m?

Robin: I just started competing, i didn’t do very good but i’ll get better! Hope to make the “king” 1 day!

Rod: Sounds great, everybody wants to be the king one day that’s why we go for 33XC. How’s load development going, What powder are you on?

Robin: H50BMG current load is 123.1 grains pushing the 300 grain Berger at 3138 fps!

Rod: Can you give us the specs on this 33XC?

  • Bat CT action
  • Bartlein 33″ 1.350″ straight barrel T5 terminator
  • Bix n Andy benchrest Trigger Set at 2.75oz
  • ARS ELR Chassis (10lbs of lead shot added to the tanks)
  • Phoenix bipod, Protector rear bag

I did try some n570! Went with a middle load from what Ryan Pierce used! 116.8 grains! Got a tight bolt with it, so I sold the 570!

Rod: That’s awesome data there Robin

What glass do you have on your rifle?

Robin: I forgot to add the Nightforce 7×35×56 f1 moa

1 reason i didn’t do well at the Arena 2 weeks ago, I forgot to rezero my windage after Friday practice! Wind was 180° opposite on Saturday, so I had about 10 minutes dialed right!

Rod: Remember the fundamentals – to always rezero your turrets after finishing a shooting session before getting off the firing line! Thanks Robin for that helpful chat!

Thanks for everyone who has contributed to this article in one way or another. Feel free to get in touch with me.

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