diff --git a/nautilus_core/adapters/src/databento/python/live.rs b/nautilus_core/adapters/src/databento/python/live.rs
index 40b954bdc770..ce48dc424f27 100644
--- a/nautilus_core/adapters/src/databento/python/live.rs
+++ b/nautilus_core/adapters/src/databento/python/live.rs
@@ -21,13 +21,12 @@ use dbn::{PitSymbolMap, Record, SymbolIndex, VersionUpgradePolicy};
 use indexmap::IndexMap;
 use log::{error, info};
 use nautilus_core::{
-    ffi::cvec::CVec,
     python::{to_pyruntime_err, to_pyvalue_err},
     time::{get_atomic_clock_realtime, AtomicTime, UnixNanos},
 };
 use nautilus_model::{
     data::{delta::OrderBookDelta, deltas::OrderBookDeltas, Data},
-    ffi::data::deltas::orderbook_deltas_new,
+    ffi::data::deltas::OrderBookDeltas_API,
     identifiers::{instrument_id::InstrumentId, symbol::Symbol, venue::Venue},
     python::data::data_to_pycapsule,
 };
@@ -237,14 +236,11 @@ impl DatabentoLiveClient {
                             let buffer = buffered_deltas.entry(delta.instrument_id).or_default();
                             buffer.push(delta);
 
+                            // TODO: Temporary for debugging
                             deltas_count += 1;
                             println!(
-                                "Buffering delta: {} {} {:?} flags={}, buffer_len={}",
-                                deltas_count,
-                                delta.ts_event,
-                                buffering_start,
-                                msg.flags,
-                                buffer.len()
+                                "Buffering delta: {} {} {:?} flags={}",
+                                deltas_count, delta.ts_event, buffering_start, msg.flags,
                             );
 
                             // Check if last message in the packet
@@ -266,11 +262,9 @@ impl DatabentoLiveClient {
                             }
 
                             // SAFETY: We can guarantee a deltas vec exists
-                            let instrument_id = delta.instrument_id;
                             let buffer = buffered_deltas.remove(&delta.instrument_id).unwrap();
                             let deltas = OrderBookDeltas::new(delta.instrument_id, buffer);
-                            let deltas_cvec: CVec = deltas.deltas.into();
-                            let deltas = orderbook_deltas_new(instrument_id, &deltas_cvec);
+                            let deltas = OrderBookDeltas_API::new(deltas);
                             data1 = Some(Data::Deltas(deltas));
                         }
                     };
diff --git a/nautilus_trader/adapters/databento/data.py b/nautilus_trader/adapters/databento/data.py
index 5ef62248918a..bdd32426e01b 100644
--- a/nautilus_trader/adapters/databento/data.py
+++ b/nautilus_trader/adapters/databento/data.py
@@ -41,7 +41,6 @@
 from nautilus_trader.model.data import Bar
 from nautilus_trader.model.data import BarType
 from nautilus_trader.model.data import DataType
-from nautilus_trader.model.data import OrderBookDelta
 from nautilus_trader.model.data import QuoteTick
 from nautilus_trader.model.data import TradeTick
 from nautilus_trader.model.data import capsule_to_data
@@ -137,8 +136,6 @@ def __init__(
         self._buffer_mbo_subscriptions_task: asyncio.Task | None = None
         self._is_buffering_mbo_subscriptions: bool = bool(config.mbo_subscriptions_delay)
         self._buffered_mbo_subscriptions: dict[Dataset, list[InstrumentId]] = defaultdict(list)
-        self._buffered_deltas: dict[InstrumentId, list[OrderBookDelta]] = defaultdict(list)
-        self._buffering_replay: dict[InstrumentId, int] = {}
 
         # Tasks
         self._live_client_futures: set[asyncio.Future] = set()
@@ -492,11 +489,6 @@ async def _subscribe_order_book_deltas_batch(
             ids_str = ",".join([i.value for i in instrument_ids])
             self._log.info(f"Subscribing to MBO/L3 for {ids_str}.", LogColor.BLUE)
 
-            # Setup buffered start times
-            now = self._clock.utc_now()
-            for instrument_id in instrument_ids:
-                self._buffering_replay[instrument_id] = now.value
-
             dataset: Dataset = self._loader.get_dataset_for_venue(instrument_ids[0].venue)
             live_client = self._get_live_client_mbo(dataset)