Why is the .270 Winchester so under loaded?

[Hunter270Win]

I just saw the factory .308 150gr Superfremonace load from Hornady is being loaded for 3000fps.

If this is the case how come the .270 Win couldn’t be loaded for 150gr for let’s say 3200fps.

It just seems that manufacturers aren’t utilizing the .270 Win for its full potential. Thoughts?

 

[gerry35]

Hodgdon doesn't list Superformance for the 270 Win from what I could see so it might not be a good match for it. In the bigger 6.8 Western case they are getting a bit over 3000 fps with the 150 gr Hornady Interbond and 3090 fps with the 145 gr ELD-X.

In general though it's hard to sell new rounds if you upgrade the old ones. These companies are under loading the old stuff and loading their new cartridges to the gills. Look at what the 30-06 and 7mm RM are getting these days with the newer powders.

 

[seand]

The 270 win is not an anemic cartridge at all, its SAAMI pressure limit is 65ksi. A 150 at 3200 would be more than 65ksi.

It’s not just case capacity, it’s bore diameter too. A smaller bore diameter reduces velocity because the area the pressure pushes against is smaller.

 

[Hunter270Win]

The 270 win is not an anemic cartridge at all, its SAAMI pressure limit is 65ksi. A 150 at 3200 would be more than 65ksi.

It’s not just case capacity, it’s bore diameter too. A smaller bore diameter reduces velocity because the area the pressure pushes against is smaller.

But if it has more case capacity and a higher pressure rating, surely it should outperform the .308 when comparing 150gr bullets, no?

I’m still new to this btw.

 

[blkqi]

But if it has more case capacity and a higher pressure rating, surely it should outperform the .308 when comparing 150gr bullets, no?

I’m still new to this btw.

Not necessarily, and @seand already explained why.

A 150gr bullet at .308 diameter has a larger base diameter and shorter bearing surface than a 150gr bullet at .277 diameter.

In short, the 270 projectile is more resistant to being pushed through its bore.

 

[gerry35]

But if it has more case capacity and a higher pressure rating, surely it should outperform the .308 when comparing 150gr bullets, no?

I’m still new to this btw.

You need a slower burning powder in the 270 compared to a 308 because the bore to case capacity ratio is quite different. MagPro with a 150 gr Sierra gets to 2974 fps according to Hodgdon, you would never use something at slow in a 308. The 270 probably has a similar ratio to a 300 WSM and would use similar powders.

 

[TaperPin]

But if it has more case capacity and a higher pressure rating, surely it should outperform the .308 when comparing 150gr bullets, no?

I’m still new to this btw.

2700 is slow for a 270 - that must be a decision Hornady has made. Here’s the industry standard SAAMI velocity information that’s been pressure tested. Nosler shows loads in the 2,900 fps range which seems right.

 

[z987k]

I just saw the factory .308 150gr Superfremonace load from Hornady is being loaded for 3000fps.

If this is the case how come the .270 Win couldn’t be loaded for 150gr for let’s say 3200fps.

It just seems that manufacturers aren’t utilizing the .270 Win for its full potential. Thoughts?

Twist rate is the 270's biggest thing holding it back in factory ammo.

But 3200 with a 150 is too much. Something around 3050 is achievable with the right powder, keeping it under 65kpsi. Top powders are going to be RL17, Ramshot Hunter, RL19, N550. 24in Barrel.

 

[TaperPin]

Here’s the 308 SAAMI data:



You’ll begin to see some loads from time to time that seem crazy fast - often it’s a special powder that perfectly matches the cartridge/bullet. Other times cartridges that seem like they should do good just don’t because there’s not a powder that matches well. The 280 is a good cartridge, but the tiny bit larger 280 Ackley Improved is a great cartridge because it matches powders very well.

I love the 270 - a 140 gr Accu Bond is a great western all around rifle.

 

[seand]

The 280 is a good cartridge, but the tiny bit larger 280 Ackley Improved is a great cartridge because it matches powders very well.

The 280ai also has a SAAMI MAP pressure limit of 65ksi vs the 280rem at 60ksi.

Even beyond that, folks typically read PO ackleys book or internet loads and handload Ackleys beyond pressure limits anyway because they think they are magic.

 

[Odd1out]

Simple reason, its a older cartridge. With a ton of old rifles with lower quality metal. For safety sake and lawsuits. They use lower pressure loads

Sent from my SM-G986W using Tapatalk

 

[TaperPin]

The 280ai also has a SAAMI MAP pressure limit of 65ksi vs the 280rem at 60ksi.

Even beyond that, folks typically read PO ackleys book or internet loads and handload Ackleys beyond pressure limits anyway because they think they are magic.

I think it has a little magic dust in it - generations of shooters have had great velocities with good case life.

 

[Highvoltage1]

RL 26 will get you 3000 with a 150.

 

[jfk69]

I can get 2875-3000 fps with 140-154 grain pills in my .280, a 22” Ruger M77 MKII, so 2900 should be pretty doable in a .270 I’d think. Probably use the same powders as well, 4350, 4831, Re19, Re22, anything in that burn range.

 

[DangerRanger]

I think people think factory ammo is under loaded because we get used to hearing about handload speeds that are radically over pressure

 

[jfk69]

I think people think factory ammo is under loaded because we get used to hearing about handload speeds that are radically over pressure

Probably some truth in this. However, the .280 is known to be under loaded by the factories due to the early pumps and semi auto’s that handcuffed the cartridge from the start. I always said if Remington hadn’t borked the release of the .280 there may not have been the 7 mag.

 

[83cj-7]

My 25” 8 twist .270 Win gets 3200fps with 150 SST and 3050 with the 165 ABLR. Neither of the loads are max.

 

[35WhelenAI]

My 25” 8 twist .270 Win gets 3200fps with 150 SST and 3050 with the 165 ABLR. Neither of the loads are max.

Max based on book loads or max based on your load development? Max load in a traditional .270 Win (1-10") is on the low end of 2800 fps for a 160 gr bullet. No way pushing a 165 gr ABLR over 200 fps faster with 1" more bbl length is near safe pressure in a faster twist bbl.

I'll stand corrected with the published load data backing it up.

 

[seand]

My 25” 8 twist .270 Win gets 3200fps with 150 SST and 3050 with the 165 ABLR. Neither of the loads are max.

no no way that’s not over 65ksi.

 

[jfk69]

My 25” 8 twist .270 Win gets 3200fps with 150 SST and 3050 with the 165 ABLR. Neither of the loads are max.

Those are over max. That 165 grain load is faster than my 7mag pushes a 162 or 168 with a 24” tube. The .270 isn’t magical lol.