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Anyone who knows me knows one thing: I love tinkering around with different calibers. While the 6 Dasher has been my go-to for PRS matches for nearly four years now, I’ve also experimented with many other cartridges over time. My PRS journey began about 5 or 6 years ago with a 6.5 Creedmoor which was a stock Remington Magpul 700 at what was then called Conway Lead Distributors range near Conway Spring, KS. That range is now known as Severance Training Center (STC) and is home to the Punisher Positional.
Since venturing into PRS with my 6.5, I’ve tried several calibers in PRS matches over the years: 6 BR, 6 BRA, 6 GT, 22 GT, 25 Creedmoor, and 6 Creedmoor. While I enjoyed each of these calibers, I eventually settled on the 6 Dasher as my preferred choice for most PRS matches.
However, in 2023, due to personal and professional commitments, I found myself with less time for shooting matches. Consequently, I only participated in three club matches and one national match throughout the 2023 PRS season. Since I wasn’t heavily involved in PRS during this time, I also took a break from experimenting with different calibers.
So, how did I end up with a 25 GT?
Fast forward to 2024, and here we are. I’m back in action, participating in PRS matches, and recently found myself in Georgia for the MPA Spring Showdown. I packed my trusty Dasher load (31 grains of Varget, 109-grain Berger seated at 0.050 off, Alpha Brass, and CCI 450 primers) and made the 17-hour journey to Cool Acres Sporting Camp. I won’t delve into the details of the match, but it went well enough for me to snag a free pre-fit barrel certificate from Impact Precision, cut by Stuteville Precision, off the prize table.
After the match, I headed to Florida for a short vacation. While relaxing in an Airbnb, I browsed through barrel options online and noticed they had a 25 GT barrel in stock. Intrigued by the popularity of 25 calibers in PRS, I decided to give it a try.
Why a 25 caliber?
In my years of shooting PRS, I’ve learned that while ballistics are crucial, it’s equally important to clearly see where each shot lands on target. As I’ve gotten older, I’ve noticed a slight decline in my eyesight. Transitioning from a 109-grain bullet to a 135-grain bullet, albeit slightly slower, provides similar ballistics but produces a larger impact “splash” on target or in the dirt, making it easier to observe, especially in challenging conditions like heavy vegetation or mirage.
Why didn’t I stick with the 25 Creedmoor?
Firstly, the 25 Creedmoor performed admirably. Using mostly the 134 ELD-M’s, it produced some of the best groups I’ve achieved with a Creedmoor at 800-900 yards. However, the significant amount of powder required to achieve the desired velocity resulted in more recoil than I preferred. In PRS, the ability to spot every shot downrange and make rapid adjustments is crucial. Excessive recoil hampers this process, prompting me to explore other options.
How’s it going?
Before the barrel arrived, I researched the 25 GT and consulted with shooters who had experience with it in PRS matches. It became clear that many were achieving success with a load using the 135 Berger bullets in the 2700-2750 feet per second range, utilizing either necked-up Alpha 6 GT brass or the newer Alpha 25 GT brass. Opting for the 6 GT brass, as the 25 GT brass was scarce, and choosing CCI 450 primers, a common choice among 25 GT users, I prepared to experiment with the new caliber.
Regarding powder selection, Varget and H4350 emerged as the most popular choices. Based on recommendations, I decided to start with 37 grains of H4350, a powder I had readily available.
Although I had both Hornady 134 ELD-M’s and 135 Berger Long Range Hybrids on hand, given my positive experience with Berger 109’s, I opted for the 135’s for my initial load development.
Upon receiving the barrel, I conducted a quick break-in procedure and sighted in my Leupold Mark 5 scope during a brief range visit. Armed with 50 rounds through the barrel, I prepared for the next PRS club match. Unfortunately, heavy mirage prevented me from accurately truing my ballistic calculator during the range session, so I deferred this task to a later date, but due to a busy schedule I was not able to accomplish this before the match.
Initial velocity results from the barrel were promising:
- First 5 Rounds (0-5):
- AVG: 2695 fps
- Standard Deviation: 8.6
- Extreme Spread: 26.7
- Final Five Rounds (46-50):
- AVG: 2723 fps
- Standard Deviation: 2.2
- Extreme Spread: 5.8
At the club match, armed with 50 rounds through the barrel and a rifle untested beyond 400 yards, I faced the challenge of managing barrel speed and truing my ballistic calculator. Despite a challenging start, I managed to adapt and began to appreciate the capabilities of the 25 GT.
The shifting winds presented additional challenges throughout the match. Despite this, the 25 GT, averaging 2723-2740 feet per second, demonstrated comparable ballistics to my Dasher shooting a 109 Berger at 2850 feet per second. Transitioning to the 25 GT felt seamless, and I didn’t feel disadvantaged compared to running my Dasher.
One crucial aspect I wanted to evaluate was whether the increased recoil affected my ability to spot impacts downrange. Fortunately, this wasn’t the case. I could observe as many, if not more, impacts downrange, even in heavy mirage conditions where spotting a 109 would have been challenging.
Although the stock I used with the 25 GT was approximately two pounds lighter than my Dasher setup, I still maintained visibility of impacts. However, I’ve ordered a weight kit for the new Foundation Stock to match the weight of my Dasher setup, allowing for a direct comparison of recoil between the two calibers in future matches.
Rifle Setup:
- Action: Impact Precision 737R
- Stock: Foundation Centurion (to be fitted with Jon Wells Weight Kit)
- Barrel: Custom Rifle Barrel (CRB) cut by Stuteville Precision
- Brake: 6.5MM ACE Brake
- Trigger: Trigger Tech Diamnd Single Stage
- Scope: Leupold Mark 5, 5-25×56, MRad, PR-1
Despite a challenging start, I finished the match in 14th place, showcasing the 25 GT’s performance in variable wind conditions. Once I trued my ballistics calculator I maintained an average of 7.75 points per stage, I’m satisfied with the outcome, considering the tricky wind conditions.
- Last ten rounds fired at the match:
- AVG: 2742 fps
- Standard Deviation: 6.1
- Extreme Spread: 18.6
Early Verdict?
As I mentioned at the outset, I’ve experimented with numerous calibers in the past, and while they’ve all been enjoyable, none have ever compelled me to even remotely consider straying from my reliable 6 Dasher. With only about 160 rounds downrange with the 25 GT, I’m beginning to sense something different about it. Whether it’s the ease of spotting impact points downrange or the mild recoil, there’s an allure to this caliber that intrigues me. I intend to delve deeper into its capabilities and put it through its paces in a few more matches.
Have I stumbled upon a caliber that could potentially dethrone my trusted 6 Dasher? It’s too early to say definitively, but for the first time in four years, I find myself seriously contemplating the possibility.
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Topic starter
Posted : 24/03/2024 4:30 pm
I am back with a little update on the 25 GT project, a little over a week since the last time I took it to the range. I have played around with the seating depth and now have almost 200 rounds through the barrel.
I did end up adding a weight kit to my foundation stock and did a little bit of seat depth load development. I decided not to mess with the powder charge because the Standard Deviation (SD) and Extreme Spread (ES) have been so good; I do not see a reason to adjust it right now. Initially, I started with a 25 thousandth jump, but after some testing, I think I may switch to 35 off.
Here are the seat depths I tested at 100 yards, firing 5 rounds each: (*Note: we had 15 MPH tail winds during this test)
- 25 off – .37” group size
- 30 off – .44” group size
- 35 off – .37” group size
- 40 off – .39” group size
- 45 off – .43” group size
I was considering going a little deeper, probably up to about 50 off, but I don't have a 25 GT seating die at the moment. I've been using a 6.5 Creedmoor die, which won't go past 45 off in my GT. However, I've had really good luck with the 109 Berger Hybrid at 50 off in my Dasher, so I want to try it at some point.
How did the weight kit help with recoil?
While I don't regularly shoot a 6 GT, I did have one in the past, and the recoil was a tad bit more than my Dasher. However, I ran the 6 GT (around 2900 FPS) faster than I am running my Dasher (2800 FPS). With the 25 GT and the 135 Berger Long Range Hybrid, you can tell there is a bit more recoil even at a slower velocity. This is due to there being more powder (37 grains of H4350) and a heavier bullet (+26 grains over the 109 Berger). Adding the additional 2 lbs with the weight kit did help a lot with stability and recoil.
What is my load going to be going forward?
I am going to settle on the following load for the next few range/match sessions:
- Powder: H4350 (37 grains)
- Bullet: 135 Berger Long Range Hybrid (35 off)
- Brass: Alpha Munitions 6 GT necked up
- Primer: CCI450
As I continue to document this journey, I look forward to sharing further insights and observations. Stay tuned for updates on velocity progression and performance enhancements.
This post was modified 2 months ago by prvboss
Topic starter
Posted : 30/03/2024 6:55 am
Disclaimer: It is crucial to acknowledge that working with live ammunition and firearms is inherently dangerous and should be approached with the utmost caution and responsibility. The information provided in this article is for educational purposes only and does not substitute for professional guidance or expertise. See full disclaimer at bottom of article.
After taking a few weeks off from the 25 GT due to work and other obligations, I was finally able to make it to the range and finish up some load development. After talking with the winner of the Box Canyon Showdown, who won the match shooting a 25 GT, I wanted to play around with some Hodgdon Varget because at this point, I had only tried Hodgdon H4350.
Through research and discussion, I had decided I was going to start with 33.4 grains of Varget in order to ensure I started at a safe pressure, and then work my way up to 34.2. Although some have been able to go much higher than 34.2 grains, I do not intend to run this super-fast. I really want the ballistics to line up close to a 109 Berger Long Range Hybrid at 2820-2850, so it is similar to what I have been running in the Dasher for the last 4 years.
Having done load development hundreds of times over the years, I do not load a ton of rounds in the initial phase of the testing. I pretty much load 4 rounds per charge weight and pick a seat depth that I know shoots well at a similar speed. Having played around with H4350, I knew that 0.025 and 0.035 off the lands shot extremely well in this barrel, and with 0.035 being the best, I started there.
Here are the powder charges I decided to start with:
- Varget – 0.035 off unless indicated below
- 33.4
- 33.6
- 33.8
- 34.0 (0.025 off)
- 34.0
- 34.2
- H4350 – 0.035 off
- 36.6
- 36.8
I threw in two H4350 loads I have been wanting to play with. I was experiencing a little bit of pressure signs on my primers at 37 grains of H4350, but after taking some measurements, I am almost certain it is because the virgin 6 GT brass I am expanding has about 4-5 thousandths bump, which is a little more than I would like to have. You really want that to be in the 2-3 thousandths range, with 3 being max. In my experience, anything over that and you will start to get pressure signs.
Range Trip:
With everything loaded and ready to go, I headed out to the range to start this testing. Just for reference, the temperature that morning here in Kansas was about 46 degrees Fahrenheit, and the winds were extremely light at 2-3 MPH from the Southeast. This made for a very pleasant morning.
Setup:
- Load:
- Virgin Alpha 6 GT Brass necked up with a Sinclair Expanding Mandrel
- CCI450
- Berger 135 Long Range Hybrid
- Varget (33.4, 33.6, 33.8, 34, 34.2)
- H4350 (36.6, 36.8)
- Gear Used:
- Garmin Xero C1 Pro Chronograph
- Rifle: Impact Action, Foundation Stock, Leupold Mark 5, Hawkins Rings, ACE Brake, CRB Barrel, TriggerTech Diamond Trigger, Hawkins M5 Bottom Metal, MDT Mag, Harris Bipod.
- Plywood board at 600 Yards
- 2’ x 3’ white paper with an orange circle in the center (x2)
The Process:
I colored the bullets of the loaded Ammo with Sharpies:
- 33.4 Varget – No Color
- 33.6 Varget – Orange
- 33.8 Varget – Green
- 34.0 Varget – Red (0.035)
- 34.0 Varget – Green (0.025)
- 34.2 Varget – Blue
- 36.6 H4350 – Red
- 36.8 H4350 – Blue
You really want to get to the range in the morning or evening when the mirage and wind are the lowest. It is almost impossible to do this in the middle of the day when the mirage washes out your aiming point. Hang both pieces of paper on the plywood board at 600 yards. In this case, it was at 575 yards because that is where this range already has a board in place.
Shooting sequence one:
- Left Paper
- 33.4 (Varget)
- 33.6 (Varget)
- 33.8 (Varget)
- Right Paper
- 36.6 (H4350)
- 36.8 (H4350)
- 34.0 (Varget) (0.025)
After firing all the rounds from the above loads, I went downrange to verify and mark the holes in the paper. The Sharpie on the bullet will leave the color on the edge of the hole. If you shoot a load that is not colored with a Sharpie like I did with 33.4, it is easiest if you mark all the color ones first and then the leftover holes are the ones with no marks.
Shooting Sequence two:
- Left Paper:
- 34.0 (Varget) (0.035)
- 34.2 (Varget)
- Shooting Process Complete
Note: During the shooting process, you need to monitor your barrel temperature. When you go out on a morning like I did when it is in the 40s, barrel heat is not going to be a major issue.
The Results:
Okay, the part everyone is looking for. Once I completed this process, I loaded everything up and headed back to the house. It is much easier to use a computer and layout the targets on a big table at home than trying to do all of this at the range. What I was looking for at 575 yards was the loads with the least amount of vertical dispersion. I am not worried about the wind or left and right of the aiming point. Once I got home, I was able to measure the difference in vertical from all the rounds fired across all the powder charges.
Here are the results:
Analysis of the results shows that just about any one of these loads will shoot well enough to win a PRS match. I will also add that I have not done much seat depth testing with any of these powder charges other than the 37 grain H4350 that I started with. The next step in the process would be to conduct a seat depth test at 575 yards with whichever powder charge I go with. In this case, I am going to go with the 34 grain Varget.
One note I would like to add is as the morning went on, the mirage picked up quickly. This can impact your aiming point and cause bigger groups.
Overall, in my barrel, Varget seems to produce the best SDs and ESs. I did load up about 40 of each of the loads below and took it to the range. On the day I took it, the temps had climbed to 75-80 degrees, and the barrel now had about 70 rounds on it. The barrel was completely clean with about 20 rounds of fouling before running this 575-yard test.
Here are the last 10 rounds of the 40:
My final load:
Right now, I am sitting at around 330 rounds on this Custom Rifle Barrel (CRB), and unless something changes in the next 750-1,000 rounds, I am going to run the following load in practice and the next few matches.
Final 25 GT Load Data:
- Powder: 34g Varget
- Bullet: Berger 135 Long Range Hybrid
- Jumped at 0.035 from the lands
- This is 2.069 OAL using a 3-24 insert on a Hornady Comparator Tool
- Primer: CCI 450
- Avg FPS: 2725
This probably ends my major exploration with load development for the 25 GT. If my groups start to open up at this point, I will probably just play around in the areas I know it shoots well.
If you have read my first article about the 25 GT in which I talk about how much I enjoy shooting this cartridge, just for the record, that has not changed. I really enjoy shooting the 25 GT and will probably finish out the year shooting it at club matches.
As age sets in on my eyes, it is becoming harder to see the impact points on target with the smaller 6MM bullets, which is what sparked my interest in 25 caliber bullets a few years ago when I played around with the 25 Creedmoor. Keeping the ballistics the same as the 109 Berger by reducing the speed helps with the transition. Also, the recoil is very manageable, and in the 330 rounds I have sent down range so far, I do not feel like I have missed a single impact due to recoil.
Thanks for reading and Enjoy the Precision Rifle Process!
Disclaimer: It is crucial to acknowledge that working with live ammunition and firearms is inherently dangerous and should be approached with the utmost caution and responsibility. The information provided in this article is for educational purposes only and does not substitute for professional guidance or expertise. Loading ammunition requires in-depth knowledge, experience, and adherence to established safety protocols. It is essential to consult with a qualified professional, such as a certified firearms instructor, experienced reloader, or ballistics expert, before attempting to develop or modify ammunition loads. Improperly loaded ammunition can lead to catastrophic consequences, including injury or death. Any experimentation with ammunition should be conducted within the parameters specified by reputable reloading manuals and manufacturers’ recommendations. Additionally, local laws and regulations regarding firearms and ammunition must be strictly followed. It is the responsibility of the individual to ensure compliance with all applicable legal requirements. The authors and publishers do not assume any liability for the use or misuse of the information provided in this article. Readers are solely responsible for their actions and should exercise caution, seek professional guidance, and prioritize safety above all else when working with firearms and live ammunition. Always prioritize safety, seek appropriate training, and consult with professionals before engaging in any activities related to firearms, ammunition, and reloading.
Topic starter
Posted : 13/04/2024 3:18 pm
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